Anger and Hatred

On Stardate 3372.7, Mr. Spock, first officer of the starship USS Enterprise, abruptly requests a leave of absence to his home planet of Vulcan after displaying irrational behavior for several days. Captain Kirk and Dr. McCoy witness one of Spock's outbursts, including the throwing of a bowl of Vulcan plomeek soup specially prepared for him by Nurse Chapel, and McCoy agrees Spock needs some "time off".

Kirk is baffled by the strange behavior and Spock's unwillingness to tell him more than "I need rest", but honors Spock's request and diverts the Enterprise to Vulcan. Soon however, Kirk receives a priority signal with orders to proceed to Altair VI to represent the Federation at an inauguration ceremony for the planet's new president. Kirk tells Spock his leave will have to be delayed. Later, Kirk asks Mr. Chekov how long it would take to get to Altair if they diverted to Vulcan just long enough to drop off Mr. Spock; Chekov replies that Spock has already ordered a course change to Vulcan.

Kirk confronts Spock, who says he has no memory of having changed the order. Kirk orders him to report to sickbay for a full examination. Once there, Dr. McCoy discovers Spock's blood chemistry is extremely active and has the presence of unknown hormones. If the condition persists, Spock will die in eight days from the physical and psychological stress. Spock does not wish to discuss what is currently affecting him, but Kirk demands an explanation.

Seemingly embarrassed, Spock informs that his condition is called Pon farr, a very personal biological syndrome that all Vulcan males painfully endure periodically throughout their adult life. During this time, they must join with their wives, or die. Spock compares his need to return to Vulcan to the need for eel birds of Regulus to return every eleven years to the caverns where they hatched, and also to salmon of Earth who must return to the stream where they were born to spawn. Kirk gets the idea that it is essentially Spock's mating season.

Kirk contacts Admiral Komack at Starfleet Command Sector 9, and requests permission to divert to Vulcan. The Admiral denies permission, but Kirk ignores the order, arguing there are already two other starships attending the Altair VI ceremony. Spock seems to calm down once he learns Kirk is doing what he can.

The Enterprise finally arrives at Vulcan, and Spock invites Kirk and Dr. McCoy to accompany him to the surface. Once there, Kirk comments on Vulcan's extremely harsh environment and its atmosphere which is thinner than Earth's.

Spock explains to them that Vulcans are married as children with the understanding that they will fulfill this commitment when they become adults. His bride T'Pring, who was betrothed to him at the age of 7, awaits him. He must enter Kunat kalifee, his family's traditional place of the Vulcan marriage ceremony.

T'Pau, a highly respected member of Vulcan society, and best known as the only person to ever turn down a seat in the Federation Council, arrives to conduct the ceremony.

T'Pring arrives accompanied by Stonn, a pure-blooded Vulcan, who is obviously her lover. She invokes kal-if-fee, her customary right to a physical challenge between Spock and Stonn. But instead, she picks Kirk to be her challenger to fight Spock. The duel pains Spock, and he asks that T'Pau forbid it because Kirk "does not understand, he does not know", but T'Pau allows it. She tells Kirk to decide, telling him another champion will be selected if he declines. Kirk accepts the challenge, thinking he can let Spock win — then discovers that this is a fight to the death.

Regardless of Spock's condition, he displays superior strength and agility. Kirk is weakened by Vulcan's heat and thinner atmosphere and must struggle harder against Spock's strength. McCoy objects, telling T'Pau that Kirk is seriously disadvantaged, and suggests he inject Kirk with a tri-ox compound to compensate. T'Pau allows the injection. The combat continues and Spock garrotes Kirk with a traditional weapon, at which point McCoy pronounces the Captain dead and has his body beamed back to the Enterprise.

With the battle over, Spock now realizes what has happened. He gives up his claim on T'Pring and sadly returns to the ship, though not before questioning T'Pring on her choice of Kirk as her champion; in a display of logic that impresses Spock in its flawlessness, T'Pring explains that with Spock's name now near-legendary among their people, she developed a mutual attraction with Stonn rather than becoming the consort to such fame. However, since she could only legally divorce Spock through the kalifee, and allowing Stonn to take the challenge as her champion would risk losing him, she instead chose Kirk, knowing that regardless of the outcome, she and Stonn would be together - as Spock would either be dead or in prison for killing Kirk.

On the ship, Spock announces his intention to resign from Starfleet and submit himself to whatever consequences await him for killing Kirk. However, he finds his Captain alive and well, and expresses overt joy (unusual for a normally emotionless Vulcan) in the full witness of McCoy and Chapel. McCoy and Kirk then explain that McCoy actually injected the Captain with a neuroparalyzer drug that simulated death but merely knocked him out. Spock says that when he thought he had killed the Captain, he found that he had lost all desire for T'Pring, and the madness was gone. Furthermore, Kirk is let off the hook for disobeying orders when Starfleet retroactively grants permission to divert to Vulcan at T'Pau's request.

Jedi Knights Obi-Wan Kenobi and Anakin Skywalker are leading a mission to rescue the Republic's leader Chancellor Palpatine, who has been kidnapped by the Separatist leader General Grievous. The Jedi maneuver to Grievous' ship, where they successfully locate the Chancellor. Sith Lord Count Dooku appears, and Anakin kills him in a lightsaber duel. The Jedi free the Chancellor and attempt to escape, but are captured by General Grievous. Obi-Wan and Anakin manage to break free, but Grievous traps the Jedi and the Chancellor inside the damaged cruiser and leaves in an escape pod. Anakin is forced to crash-land the ship on one of Coruscant's landing tracks.

On Coruscant, Anakin is reunited with his wife, Padmé Amidala, who tells him that she is pregnant. Anakin is overjoyed at this news. However, Anakin is troubled by visions of Padmé dying in childbirth—visions similar to those he had of his mother just before she died. Later, Obi-Wan privately tells Anakin that the Jedi council wants him to spy on the Chancellor because they believe him to be corrupt, an order Anakin resents since the Chancellor has become something of a mentor to him. As the Chancellor's bodyguard, Anakin develops a close friendship with Palpatine, who subtly manipulates Anakin in their conversations, making him distrust the Jedi. Palpatine claims to know of an ability to prevent death.

Obi-Wan is sent to Utapau, where he engages and kills General Grievous. Meanwhile, back on Coruscant, Palpatine reveals himself to Anakin as the Sith Lord Darth Sidious, who has been controlling the Republic and the Separatist movement. Anakin leaves to expose him to the Jedi Council. Jedi Master Mace Windu arrives at the Chancellor's office shortly thereafter and eventually subdues Sidious in a lightsaber duel. Just as Anakin arrives, Windu is about to kill Sidious. Anakin quickly disarms Windu, believing Sidious holds the only way to save his wife. Windu is consumed by Sidious's torrents of Force lightning, being thrown out a window to his death. Anakin then submits to the dark side of the Force and becomes Sidious's Sith apprentice: Darth Vader. He then orders Vader to kill all Jedi inside the Jedi Temple, then to go to the Mustafar system and eliminate the Separatist leaders.

Darth Sidious orders clone troopers across the galaxy to turn against their Jedi Generals by enacting a pre-programmed directive, Order 66. Numerous Jedi across the galaxy are seen being exterminated, although both Yoda and Obi-Wan survive. Meanwhile, Darth Vader and the 501st Legion storm the Jedi Temple and slaughter all of the Jedi, including younglings, in the temple. Afterwards, he goes to Padmé and tells her the Jedi have attempted to take over the Republic and leaves for Mustafar, where he slaughters the Separatist leaders. Senator Bail Organa rescues Obi-Wan and Yoda, and brings them to the Jedi Temple before heading to the Senate building. Sidious (as Palpatine) informs the Senate of a Jedi plot to overthrow the Republic. As a result, he announces that the Republic will be reorganized into the "first Galactic Empire".

In the Jedi Temple, Obi-Wan and Yoda stand in shock over the bodies of the younglings and reconfigure a signal to warn any remaining Jedi to keep away. Obi-Wan looks into the security recordings and, to his horror, sees a hologram of Vader carrying out the orders of Darth Sidious and kneeling to him. Though he initially refuses, Obi-Wan eventually agrees to find and kill Anakin. Obi-Wan then meets with Padmé, who refuses to believe his claims about Anakin's fall to the dark side. When she departs for Mustafar, Obi-Wan secretly stows away onboard. When the couple is reunited, Padmé pleads with Vader to leave public life with her, but he refuses, believing that he can overthrow Sidious so that he and Padmé can rule the galaxy together. Vader sees Obi-Wan emerge from Padmé's ship, and suspects her of betraying him. Enraged, he uses Force Choke to choke Padmé into a coma.

Obi-Wan and Vader break into a vicious lightsaber duel. The duel brings them out of the facility to unprotected areas of the volcano planet. Obi-Wan eventually gains the advantage of higher ground, and when Vader attempts to attack again, Obi-Wan swiftly dismembers him, removing his legs and non-mechanical arm and leaves him to die. While screaming in agony Vader tumbles down the embankment to the edge of the lava where he catches fire, sustaining near-fatal burns and critical lung damage. Obi-Wan leaves Mustafar with Padmé and Vader's lightsaber, reluctantly leaving Vader to die. On Coruscant, Yoda had engaged Palpatine in a duel which worked its way into the main Senate Conference Stadium. The duel ends unfinished and Yoda is forced to flee and is once again air lifted by Bail Organa. Shortly after Vader's defeat, Palpatine rescues Vader and sends his troops to revive his apprentice.

Padmé is given medical assistance. However, she has lost her will to live. She manages to deliver twins, a boy and a girl, and names them Luke and Leia respectively. Padmé then dies, but not before insisting to Obi-Wan that there is still good in Anakin. On Coruscant, Vader's missing limbs and damaged body parts are replaced by cybernetic prostheses and implants. Vader is put into a full suit of black armor and is sealed in a respirator mask, which will allow him to survive his injuries. Upon inquiring with Sidious about Padmé's condition, Vader is informed that, in his anger, he himself killed Padmé. Vader unleashes a furious scream of mournful rage and destroys droids and equipment throughout the room with the Force while Sidious looks on with a malicious, contented smile, satisfied that Vader's hatred and rage has survived the mutilation of his body.

Aboard Bail Organa's ship, Obi-Wan, Yoda, and Organa agree to keep the children hidden and separated; Obi-Wan and Yoda will watch and wait until the time is ready for the Skywalker children to do their part in the battle against the Sith. Bail orders C-3PO's memory banks wiped. Padmé is given a state funeral on Naboo. Vader and Palpatine oversee the construction of a space station. Leia is taken to live with Bail Organa and his wife, while Luke is transferred to Tatooine to live with Owen and Beru.