Revenge of the Sith

Three years after the start of the Clone Wars, Jedi Master Obi-Wan Kenobi and Knight Anakin Skywalker lead a mission to rescue Supreme Chancellor Palpatine from the cyborg Separatist commander General Grievous. After infiltrating Grievous's flagship in Coruscant's orbit, Obi-Wan and Anakin battle the Sith Lord Count Dooku, whom Anakin disarms and then executes at Palpatine's insistence. Grievous escapes the damaged ship before Obi-Wan and Anakin crash-land it on Coruscant. Anakin reunites with his wife, Padmé Amidala, who tells him she is pregnant. Soon after, Anakin is haunted by visions of Padmé dying in childbirth, similar to the vision he had of his mother before her death.
Palpatine appoints Anakin to the Jedi Council as his representative. Distrusting Palpatine, the Council agrees but refuses to make Anakin a Jedi Master. They instead instruct him to spy on Palpatine, diminishing Anakin's faith in the Jedi. Meanwhile, on Utapau, Grievous relocates the Separatist leaders to the volcanic planet Mustafar. Obi-Wan travels to Utapau and battles Grievous, ultimately killing him.
Meanwhile, Palpatine tempts Anakin with the dark side of the Force, promising that it can save Padmé's life. Anakin deduces that Palpatine is the Sith Lord, Darth Sidious, and the one who orchestrated the Clone Wars. He reports this to Mace Windu, who confronts and subdues Palpatine. Desperate to save Padmé, Anakin maims Windu to prevent him from killing Sidious, allowing Sidious to kill Windu with his Force lightning. Despite being horrified by his actions, Anakin pledges himself to the Sith in return for Sidious' help in saving Padmé. Sidious christens Anakin, now known as Darth Vader. Sidious issues Order 66, which makes the obedience-conditioned clone troopers kill their commanding Jedi generals across the galaxy, while Vader commands a battalion of clone troopers to massacre the remaining Jedi in the Jedi Temple. Vader then assassinates the Separatist leaders on Mustafar, while Sidious publicly denounces the Jedi as traitors and declares himself Emperor before the Galactic Senate, transforming the Republic into the Galactic Empire.
Obi-Wan and Yoda survive Order 66 and learn that Anakin has turned to the dark side. On Coruscant, Yoda instructs Obi-Wan to confront Vader while he faces Sidious. Obi-Wan seeks out Padmé to learn Vader's whereabouts and to reveal his treachery. Padmé travels to Mustafar—unaware that Obi-Wan has stowed aboard her ship—and pleads with Vader to abandon the dark side. When Obi-Wan emerges, an enraged Vader believes Padmé has betrayed him and strangles her with the Force. Obi-Wan and Vader engage in a lightsaber duel, before Obi-Wan defeats Vader and severs his remaining limbs. Obi-Wan remorsefully denounces his former friend, who is then burned alive by a nearby lava flow. Obi-Wan retrieves Vader's lightsaber and leaves him for dead.
Meanwhile, Yoda battles Sidious on Coruscant, culminating in a stalemate. Yoda flees with Senator Bail Organa and regroups with Obi-Wan and Padmé on the planetoid Polis Massa. Padmé gives birth to twins, whom she names Luke and Leia. She dies soon after, still believing there is good in Anakin. Sidious recovers the barely-alive Vader. On Coruscant, Vader's mutilated body is treated and encased in a black, armored life-support suit. When he inquires about Padmé, Sidious claims Vader killed her out of rage, leaving Vader devastated.
Obi-Wan and Yoda conceal the twins' birth from the Sith and retreat into exile until the Empire can be challenged. As Padmé's funeral is underway on Naboo, Palpatine and Vader supervise the construction of the Death Star. Bail takes Leia to Alderaan to raise her as his daughter. Obi-Wan delivers Luke to his step-uncle and step-aunt, Owen and Beru Lars, on Tatooine. Obi-Wan settles nearby as a recluse while watching over young Luke.