S1E3 · ...and the Bag's in the River

Complete story — includes the ending

Skyler's sister, Marie, mistakenly believes that Walter Jr. is smoking marijuana and asks Hank to scare him straight. Hank takes Walt Jr. to a rundown motel to tell him about "gateway drugs". Walt and Jesse clean up the remains of Emilio, and Walt is torn between whether to keep Krazy-8 alive or kill him. While bringing Krazy-8 food, Walt collapses while descending the stairs and smashes the plate on the floor. Upon waking up, Walt reveals to Krazy-8 that he has lung cancer—the first person he tells—and they start sharing the unexpected things they have in common. Krazy-8 also sows mistrust against Jesse, warning Walt about working with a drug addict. Walt decides to release Krazy-8, but while disposing of the shards of the broken plate, he sees that a shard is missing, and realizes that Krazy-8 has concealed it to use as a weapon. When Walt confronts Krazy-8, Krazy-8 attacks him; Walt strangles and kills him with the bicycle lock restraint. Walt lies and tells Skyler he was working late at the car wash, but she has already talked to his boss and knows he quit weeks ago. That night, Walt returns home and tells Skyler that they need to talk.