Season 3

Complete listed story — includes the ending

1. Enough Nemesis to Go Around

Six months after Joan moved out, she is running her own investigation firm and helps bust female drug kingpin Elana March. Two months later, the case has gone stagnant and the key witness in the prosecution of the kingpin is murdered in a hotel elevator. To her surprise, Joan discovers Sherlock has returned with a new protégé named Kitty Winter, and is working on the case as well, after being fired from MI6. The three must find a way to get along and work together while finding the murderer, skilled hitman Kevin Elspeth. Sherlock solves the "locked room" mystery of the elevator - the murderer placed spent bullets carefully in the elevator and used an extremely powerful electromagnet to propel them into the two victims from his hotel room next to the elevator. Joan realises that while the killer brought the disassembled parts of the magnet into the hotel in luggage and packages, he could not take them out quickly. She finds the parts hidden in his shower seat. Fingerprints inside the rubber gloves used to handle the magnet identify the murderer.

2. The Five Orange Pipz

A double murder appears to be revenge for the deaths of children poisoned by GHB, the inadvertent result of cost-cutting measures taken by the Indian manufacturer of toy beads. Each of the victims received five orange beads in the mail. The father of one of the children confesses, but Sherlock deduces that he is lying. FBI agent Vince Boden refuses to provide whatever information the agency has, citing policy. Evidence vital to the case against the murdered men has gone missing, which complicates figuring out the motive for the crimes. At first, Sherlock suspects the prosecutor, US Attorney Angela White, as the collapse of her case would end her ambition to be elected to a Senate seat. White admits to being blackmailed by one of the murdered men, but denies killing them. Then Sherlock realises who the killer is. Boden wanted the case to never come to trial, so he could then easily steal the no-longer-needed evidence: the GHB, an addictive drug worth millions of dollars on the black market.

3. Just a Regular Irregular

Mathematician Harlan Emple comes across a dead body packed in mothballs while participating in a "math hunt", a number game with a puzzle involving Belphegor's prime. When another body is found, it is believed that the game is intended to be a death trap for mathematicians or, as it turns out, one mathematician in particular. Meanwhile, Joan tries to convince Kitty, who was a rape victim, to join a support group.

4. Bella

Software developer Edwin Borstein has created an artificial intelligence (AI) program called Bella, and he hires Sherlock because someone has broken into his company and stolen a copy of the program. Sherlock takes the case, not because he finds it interesting, but because he does not believe AI is achievable. He solves the theft case, but then Borstein dies from a fatal epileptic seizure, seemingly caused by Bella through rapidly cycling images displayed on Borstein's monitor. Sherlock finds a program hidden on a music CD death metal fan Borstein was given. Eventually he traces the criminal to a think tank that believes that AI is the greatest threat to human existence. He is confident that its leading light, computer science professor Isaac Pike, is responsible, but a devotee confesses, despite having no programming skills. Meanwhile, Joan's boyfriend Andrew receives a job offer that would take him to Copenhagen, and Joan wonders if Sherlock is responsible for it.

5. Rip Off

A severed hand is seen in a street puddle. It belongs to the corpse of Orthodox Jew Moshe Shapiro. Shapiro owned a Postal Unlimited store nearby. A hidden safe contains Moshe's ledger. Moshe turns out to have been a diamond smuggler. Sherlock deduces that weightlifter Dana Kazmir ripped the hand off. Kazmir confesses to the murder and provides a list of three other people he was supposed to kill, which includes Amit Hattengatti, the store's only employee. The NYPD intercept a cash payment to Kazmir, and the envelope matches the office supplies in Moshe's shop. Amit was actually Moshe's smuggling partner. He had plotted with Kazmir and Kazmir's corrupt lawyer to make it look like he was a murder target to deflect suspicion. (Moshe had reformed and was planning to end his smuggling operation.) Kazmir, doomed to jail anyway, lied in return for a payout for his family. Amit eventually names his diamond supplier. Meanwhile, Sherlock gets Kitty to sign a non-disclosure agreement after finding Joan's unpublished "The Casebook of Sherlock Holmes". Gregson punches a policeman, who had twice abused Gregson's daughter Hannah.

6. Terra Pericolosa

Joan returns from Denmark. Kitty is called to a museum, where valuable old maps and a security guard are missing. The guard is dead. One particular map was the target; the rest were taken just to camouflage that fact. That map, "The County of King James, Virginia, 1794", was loaned to the museum by a now-deceased member of the Bray family decades before. The family's charitable organization still exists, and is run by Margaret Bray. The thief is ex-cartography student Stuart Zupco, who turns up dead. The missing maps are found at his framing shop, but the Bray map is a forgery. It and the original are almost identical, except the course of a section of a river has been altered. That one change provides the motive. A billion-dollar casino, envisioned by real estate mogul William Hull, is to be built on land affected by the alteration. Bray's family owns property neighboring the site; the casino would send the value of the surrounding real estate sky high. Bray was the killer; without the map change, the project would have to be abandoned.

7. The Adventure of the Nutmeg Concoction

Joan's new client wants to find out about her sister, Jessica Holder, who disappeared five years before. The smell of nutmeg was detected at the site of Jessica's disappearance and those of others. Noah Kramer, a married lawyer with whom Jessica was having an affair, told her that his client, Raymond Carpenter, was guilty of several murders; she was going to tell the police. In Sing Sing, Carpenter admits that he outsourced her murder, but the killer is now dead. A new crime scene with the scent of nutmeg is found. The murders are connected only by the same cleaner being employed to dissolve the bodies, who masked the odors of the cleaning concoction with nutmeg. At an institute which offers certification in cleaning up crime scenes, Sherlock spots a lurid mural featuring nutmeg. The artist, Conrad Woodbine, is the cleaner, but refuses to identify any of his clients and is himself murdered and cleaned. Carpenter's youngest son was Woodbine's apprentice. He killed him on Carpenter's orders. Sherlock and Joan promise that if Carpenter calls his son and tells him to work with the police, they will make sure that he is put in a safer prison. Carpenter agrees.

8. End of Watch

Flynn, a Highway Patrol officer, is murdered; his sidearm had been replaced with an airsoft gun. Flynn was a drug addict. He stole guns from the police department's Rodman's Neck Armory, replacing them with airsoft guns, and sold the real weapons to fund his addiction. His buyer, Buros, a wanted arms dealer, already had buyers lined up for the prized military-grade police weapons, but Flynn, now clean, refused to obtain more for him. Buros killed Flynn, as he would be given an inspector's funeral attended by thousands of police officers, leaving the Armory poorly guarded, but Flynn's crimes came to light and his special funeral was canceled. So Buros kills another officer to cause another such funeral. He steals the weapons. Watson identifies the white fibers he left at both murder scenes as upholstery fibers - Buros plans to ship the weapons hidden inside furniture. He is arrested after his cargo shipment is traced. Meanwhile, Sherlock finds the person posting his personal statements made in sobriety meetings on a recovery blog, and insists they take the blog down, as anonymity is vital for the success of the meetings.

9. The Eternity Injection

A nurse Joan knew is missing. The woman's trail leads to an illegal human drug trial of EZM-77, a time-dilating substance. Five test subjects were injected. The higher the dose the madder they went (one killed the missing nurse, who administered the drug) and they die or are murdered. Carlisle, on the lowest dose, survives and his interview leads to Purgatorium, a company which paid the test subjects $150,000 up front and promised the same amount every year. The drug's inventor, Dwyer Kirk, takes responsibility for the deaths. His sponsor, James Connaughton, paid for Kirk's education and gave his aunt a stipend to help raise him. When Connaughton learned that he was dying, he approached Kirk, who agreed to try to develop a "pharmaceutical fountain of youth" so that its time-dilating properties would make his last days feel like years. The trial subjects were executed to cover it up. Connaughton's new nurse connects him with Purgatorium and with two hitmen he hired to murder the test subjects. The police come for Connaughton, who appears non-responsive; he has injected himself with EZM-77, hoping to "extend" what little time he has left to live.

10. Seed Money

An elderly couple dies in bed. They are inadvertent casualties of another crime committed elsewhere in the building. Someone burned rubber in the basement, which emitted a toxic gas. Sherlock finds a burned body with a tire around his neck. Clay Dubrovensky was the second floor tenant who worked for the criminal SDS Cartel, growing marijuana for them. A valuable orchid, the last of its kind, grows in the greenhouse. Barbara Conway, from AgriNext, bought an orchid from Clay. Sherlock examines both plants and realizes that Clay cloned the orchid twice. Two AgriNext executives are murdered by the same burning tire necklace method, and their bodies dumped in front of the AgriNext building. However, the rope is different from that used in Clay's murder. Conway admits that AgriNext offered Clay a job and was trying to buy out his relationship with the SDS. The police arrest the SDS member guilty of the AgriNext murders. He denies killing Clay. Conway turns out to have killed Clay because he was seeing his ex-girlfriend again.

11. The Illustrious Client

A woman is murdered, and her premortem back scars resemble Kitty's. A burner phone left at a bar the woman was at leads the NYPD to a suspect, Simon de Merville. Simon works for a brothel that kidnaps illegal immigrants, and in his property is the body of one of the brothel's suppliers, as well as women captives. Simon might have been injured during the lethal confrontation with the supplier and went to his sister Violet for assistance. Kitty beats Violet into cooperating with the NYPD. Violet calls Simon to allow the NYPD to triangulate the call. Simon is aboard a boat; Osweiler, a bartender and former neighbor of Simon's has one. However, the boat, stored at the owner's house, is burned, with Simon locked inside. At the morgue, Kitty inspects the body and insists that Simon was not her rapist; she had broken her captor's fingers in her escape, and Simon's fingers are intact. Later, Joan, who has settled into her new job at the insurance firm, calls her new boss, Del Gruner. Kitty, overhearing the conversation, recognizes the voice of her rapist.

12. The One That Got Away

Del Gruner abruptly fires Joan. Sherlock begins exploring the backgrounds of kidnapped and murdered women who match Gruner's modus operandi. They track down Tabitha Laird, a coworker of Gruner's at a charity to which he donates his time and money. Laird's adopted son turns out to be the child of Gruner and one of the victims on Sherlock's list. Kitty secretly captures Gruner, unaware of the evidence tying him with his crimes. She prepares to kill him and dissolve his body using a corrosive liquid. Sherlock finds her and mentions the new evidence. He then says that he will not stop her from doing whatever she decides to do, and that she will always be his friend. Kitty burns most of Gruner's face off with the concoction and leaves him to be found by the NYPD. She leaves for an unknown location.

13. Hemlock

The wife of missing lawyer Steven Horowitz hires Sherlock to find him. Sherlock and Joan discover that he did not tell his wife he had been fired by his firm. They find out that he went to work for a debt collection agency and was given a debt package worth millions. Sherlock and Joan try to narrow down the pool of suspects from the thousands of debtors. It turns out that Horowitz had a change of heart after seeing the hardships suffered by the debtors and forgave what he had not yet collected. One of those released from their financial burden is a man named Downey. A company wants to create a ski resort; Downey is the sole holdout, refusing to sell his house, which happens to be at the center of the resort. Horowitz's former boss killed him because he stood in the way of the law firm collecting millions in fees from the developer. Meanwhile, Andrew asks Joan to dinner to meet his father for the first time. Sherlock warns her that this is a significant step in their romantic relationship, but she dismisses the idea, until she discovers she is wrong. She concludes she must break up with Andrew. While she is doing so, he is poisoned.

14. The Female of the Species

Elana March tells Joan she had Andrew murdered in revenge. Sherlock enlists Detective Bell to help him find two missing pregnant zebras stolen from a zoo. A trademarked color provides the first clue; the color is only used on delivery vans for one company. They eventually find the zebras, who have given birth. They also find a veterinarian, shot dead; he was forced to help with the induced premature births. They later find a quagga, which went extinct over a century before. The zoo's staff are gathered at the police station. Sherlock identifies the real murderer, a PhD student. The killer escapes police surveillance through an old speakeasy tunnel. Realizing that the student needs to raise funds for his getaway, Sherlock wins the online auction for the second quagga and sets a trap. Later, Joan receives a letter from Moriarty. It says that she had Elana murdered because Moriarty feels that she will have further interactions with Sherlock, and secondarily Joan as well, so no interloper can be allowed to interfere. Despite the confession, Sherlock doubts that they will find any evidence to connect Elana's murder to Moriarty.

15. When Your Number's Up

Sherlock and Joan investigate two murders in which the killer leaves envelopes of cash on the victims equating to their "worth". The probe leads the two to investigate an airline crash which killed over 80 people and the amount that each would receive as wrongful death compensation according to an equation formulated by attorney Arlen Schrader. When Dana Powell, the wife of one of the crash victims, reports being shot at from her back yard, Sherlock becomes suspicious, as the first two shootings were at short range. Powell gives a seemingly tone-deaf television interview, which forces the airline to drop its method of calculation to making the same flat payment to each next-of-kin. This is puzzling, as Powell's husband was a highly successful broker. Then they discover that the husband had a fatal disease, with only a few months to live. The police obtain a search warrant for her mansion, where they find incriminating evidence. Meanwhile, Joan moves into the basement at the brownstone, and seals the interior door so that in future she will have a physically separate space, but still be able to work closely with Sherlock.

16. For All You Know

A woman named Maria Gutierrez vanishes in 2011. Her body is found three years later. Sherlock wrote a signed note found in her purse, giving his address and a meeting time, but says that he does not know her. However, he was a heavy drug user then, which caused blackouts and memory loss. Maria worked as a cleaner at the offices of Councilman Robert Barclay. Junkie Oscar Rankin knew Maria and had boasted of knowing Sherlock. Maria met with Sherlock and brought bloodied clothes belonging to Barclay. She had seen him take off the clothes and throw them away. Barclay had been having an affair with Kelsey Prior, a friend's wife, but when she tried to end it, he stabbed her. Barclay decided to dump his bag of blood-stained clothes somewhere secure, but found that it was missing. He guessed that Maria had taken it and lured her from Frobisher Motel in Bayside, where Sherlock often stashed witnesses who were in danger. Barclay killed Maria and hid her body, and Sherlock, high on drugs, forgot her. Barclay confesses. Sherlock encourages Oscar to quit heroin and gives him a paid reservation at a rehabilitation center, feeling responsible for Oscar's condition.

17. T-Bone and the Iceman

A distracted driver is killed after colliding with a van and discovering that it carries corpses. The driver's body is partially mummified, by the coolant R22. Sherlock's investigation leads to a cryogenics facility owned by a cash-strapped company that preserves the bodies of clients in the hope that future advances can revive them. There, the corpse of strangled psychiatrist Jim Sullivan, has been stolen. New patient Vance Ford provided a sketch of the murderer. Ford, however, is lying. Later, Ford is found strangled as well, which seems odd, as he was near death from leukemia anyway. The man in the sketch is actually a now-deceased actor from a movie. Ford and Sullivan were estranged cousins. Sullivan was a match for a bone marrow transplant, which could have saved Ford's life, but he refused to donate it. Ford killed him and stole the body, as the bone marrow, even after being frozen, would still be usable. Ford recruited two henchmen, who worked at the cryonics lab. With the investigation closing in, they panicked and killed Ford the same way as Sullivan. Meanwhile, Joan has trouble convincing her mother to seek help for her failing mind.

18. The View from Olympus

Galen Barrow, a driver for ridesharing company Zooss, is run over by a city cab. The murder was staged to look like professional rivalry. Barrow was an internet journalist and had begun working for Zooss recently. Registered sex offender Gordon Meadows admits to having killed Barrow; he was blackmailed into it after he broke his parole. Barrow's internet journalism employer, Lydia Guerrero, was having an affair with Barrow and was also being blackmailed by an anonymous texter. Despite her opposition, Barrow insisted on hunting the blackmailer. Zooss CEO Eric Frazier orders technician Brandon Felchek to hand over to the police computer program Olympus, which records user details and tracks all rides. A man named Patrick Kemp worked for Zooss before a mugger killed him a month earlier. Patrick turns out to have been the blackmailer at Zooss. Falchek is eventually arrested: he had cut off Patrick's access to Olympus months before on discovering that he was blackmailing users, not to protect Zooss or its users but to avoid drawing attention to his own crime; Falchek was using Olympus to stalk Felice Armistead and broke into her home where she surprised him and he broke her cheekbone.

19. One Watson, One Holmes

Everyone member "Species", real name Errol White, is killed by a now-missing samurai sword. It is later revealed that Species was secretly two people, an arrangement that allowed Species to always be online. The other half of Species is someone named Bradley Dietz. Dietz killed White when he rejected Dietz's idea of hacking think tank the Atherton Foundation, feeling that it was too dangerous. Dietz is capitalising on Everyone's sympathy for Species's death to gain power, and the hack is imminent. When confronted, Dietz is rescued by FBI Agent Branch, who provides an alibi. Branch wants Everyone to hack Atherton, which coordinates FBI and Homeland Security investigations with the internal security departments of major corporations. If Everyone hacks Atherton, the group would be arrested for treason and Branch would gain rapid promotion. Sherlock knows Branch's secret (knowingly exploiting an illegal immigrant) and will report her unless she gives the police an anonymous tip on where to find the sword. Everyone is warned about Atherton, so Dietz becomes useless to her. Branch caves in. Dietz is arrested.

20. A Stitch in Time

Debunker Garrison Boyd is killed. Boyd accused real estate developer Collin Eisley of trying to scare a woman into selling a beach house, as she was hearing unusual noises. This was actually the result of tunneling from a neighbor's house. The tunnel's target is Ruby, the world's fastest transatlantic internet cable. Ruby feeds certain investment firms. The digger is Nadim Al-Haj, an Iraqi man. Nadim eventually torches his apartment to destroy evidence and flees. Data went into a device there and came out intact, but with a delay of 4 milliseconds. Those firms had an advantage, as they received data milliseconds earlier than rivals, enough time for computer transactions. Eisley's blind trust is managed by a firm whose computer servers are not there. Eisley hired Nadim to splice in the device to flip the time advantage in favor of his investment company. After Nadim killed Boyd, Eisley paid him with a Picasso to stay quiet. The Picasso has been reported as stolen, rendering it unsellable, so Nadim will eventually make a deal with the authorities. Eisley is encouraged to do the same. Meanwhile, Hannah Gregson asks Joan to help with a case.

21. Under My Skin

A man shoots two paramedics and steals their ambulance with patient Maggie Halpern inside. A man named Wallace Turk later admits the murders. Halpern is also murdered, and her body is eviscerated by Turk's partner. Halpern was an unwitting drug mule who had received what she thought was normal surgery in Brazil. Her surgeon, Turk's brother-in-law, planted heroin inside her, then vanished. Drug gang leader Janko Stepovic uses the offices of dentist Dr Marty Ward. Bell tells Janko that if he buys the heroin, the NYPD will go after him. However, if he can help find the heroin, it will not be in the hands of rival gangs. Janko sets up a sting, but is killed elsewhere. Ward eventually gives up and agrees to tell all, including the location of two other mules' bodies. Meanwhile, a manufacturer hires Alfredo Llamosa, Sherlock's recovery sponsor, to test a security system, but fires him after Alfredo points out its flaws. They also spread false claims that he was high again. As revenge, Alfredo starts stealing their cars. Considering Alfredo his friend, Sherlock steals cars while Alfredo has an alibi. As being a sponsor is incompatible with friendship, Sherlock fires Alfredo.

22. The Best Way Out is Always Through

Judge Dennis Vaughn is killed with a screwdriver. While in New York City for a fundraiser for a governor's re-election, Vaughn had sex with one of the governor's staffers; her alibi depends on a friend, Andrea Schuster. Fingerprints on the screwdriver belong to Nikki Moreno, who escaped from a correctional facility days earlier. At the for-profit prison, run by Reform Enterprises (RE), Deputy Warden Trey McCann says that Moreno was a troublemaker. Later, McCann is murdered. Jeff Harper, a prisoner rights lawyer, says that Moreno had nothing against Vaughn, but hated McCann, and had no reason to escape or commit murder as he was close to getting her sentence reduced. He says that Moreno was forced into an unpleasant work detail recycling computers, but her prison record shows that she had asked for the detail. Moreno's body appears in a recycling bin. McCann had previously worked for another prison management company. Their executive, Perry Franklin, reveals that McCann was fired for corruption. Andrea Schuster was the re-election campaign manager. The murders were intended to cause the governor to award the new prison contract to Franklin's firm. Meanwhile, Bell discovers that his girlfriend secretly works for Internal Affairs.

23. Absconded

Testing to learn the cause of Colony collapse disorder (CCD), USDA employee Everett Keck visits Belinda's honey farm. Keck and her bees die from cyanide in his smoker. AgriNext might be behind CCD in Northeast USA. AgriNext's company executive denies murder, saying that they had been ready to counter Keck's accusations by discrediting him. Belinda's neighbor, Darryl Jarvis, had filed a complaint that Keck poisoned his bee hives with deadly mites. Jarvis actually murdered Keck. Mites did appear wherever Keck inspected hives. Keck's supervisor, Calvin Barnes, had been investigating him. This ceased once Barnes became an invalid after being poisoned. However, Keck has an alibi. Before Keck's bee-killing, CCD and academic research funding were decreasing; if CCD apparently increases, funding would rise. Meanwhile, Tara and Griffin Parker are married professors of agriculture organizing an apiary conference. Sheikh Nasser Al-Fayed, of the United Arab Emirates (UAE) royal family, will attend. The Parkers lured Nasser to the United States by manufacturing a rising CCD crisis through Keck and kidnap Nasser. Later, Nasser is on a plane (ransom paid). With the UAE's denials, there can be no kidnap charges. Proof appears that Tara was having an affair with Keck. Furious, Griffin turns on Tara, who was there when he poisoned Barnes.

24. A Controlled Descent

Oscar Rankin kidnaps Alfredo to leverage Sherlock into finding Oscar's missing sister Olivia, a fellow drug addict. Sherlock searches for Olivia with Oscar, visiting his former rehabilitation center and an active heroin den. At the den, the discarded contents of a stolen wallet contain the driving licence of Jonathan Bloom, a sexual predator who lures with heroin and is believed to have killed two women. Sherlock tortures Bloom into admitting that he took Olivia but she fought him, stole his money and heroin and escaped in a taxi. Olivia then went to an abandoned railway tunnel. There, Sherlock finds her dead of a heroin overdose. She has been dead for two days. All along Oscar knew of this. Oscar led Sherlock through the places Olivia had been to make him realize that Sherlock is as bad as he is and that it is inevitable that Sherlock will use again. Oscar then reveals a box with heroin, saying that he needs one more push. Joan texts Sherlock that they have found Alfredo alive. Sherlock beats Oscar, and picks up the box. Days later, Joan, unable to get Sherlock to talk about his relapse, reports that Morland will soon arrive.