Lelouch finally comes face-to-face with Cornelia. He uses his Geass to interrogate her about his mother's death. Cornelia doesn't know who killed Lady Marianne, and on the day of her death, when she was assigned to guard her, she was sent away...by Lady Marianne! After her demise, the Emperor ordered Schneizel to transport the body.
Before Lelouch can learn anything else, C.C. tells him to return to the Gawain immediately: Nunnally has been abducted, and taken to Kamine Island, where Lelouch had found the Thought Elevator after the incident on Shikine Island! Before they can leave for Kamine Island, they are attacked by Jeremiah, piloting an experimental weapon, the Knight Giga-Fortress "Siegfried".
While fending off the Siegfried, Lelouch desperately tries to confirm Nunnally's location and safety, but neither Ohgi's subordinate or Rivalz know where she is. As for the student council, they are found by the Black Knights while they try to extract Suzaku from the Lancelot. Before Tamaki can fly off the handle and have everyone executed, the Avalon arrives, with Cecile manning a Knightmare to engage the Black Knights and destroy the Gefjun Disturbers, allowing Suzaku to re-engage Zero. Before he can go after Zero, however, he is contacted by Cornelia...
As Tohdoh and the Black Knights fight against the bureau buildings defenses, Zero contacts him and places him in charge of the operation while he attends to other matters. At the garden in the bureau building, Suzaku finds a wounded Cornelia. She asks him to not inform the others of her condition, as it would weaken the soldiers' morale; and that Zero is making his way towards Kamine Island. Before Suzaku departs to clear Euphemia's dishonored name, she bestows upon him the title of Knight of Honor.
At the same time, a wounded Ohgi calls Kallen and tells her to go after Zero and ensure his survival, so he can realize Naoto's dream. Kallen proceeds to follow the Lancelot as it pursues Zero. At that moment, the Ganymede appears. Lloyd, realizing what Nina has attached to it, panics and calls for an immediate ceasefire as Nina holds a detonator in her hand, threatening to set off her pet project and potentially level the entire Tokyo Settlement.
Lelouch and C.C. arrive on Kamine Island. Before they can approach the Thought Elevator, however, they get caught in a psychic trap, causing Lelouch to see that countless times C.C. was killed, from being shot by soldiers to being burned at the stake. C.C. laments that everyone she has known, everyone who hated her or showed her kindness, is gone, lost to time, and she is alone. Lelouch assures her that she is not alone: they are accomplices, and that if C.C. were a witch, he would be a demon for her.
They escape the trap just in time to evade an attack from Jeremiah and the Siegfried. With the Gawain running low on power, C.C. drops Lelouch off on the island, giving him a chance to go after Nunnally while she engages Jeremiah and drags him into the ocean.
As the tide of the battle in Tokyo begins to turn against the Black Knights, Lelouch makes his final approach to the Thought Elevator. There is now nothing to stand between him and rescuing Nunnally...
...except for one: Suzaku confronts Zero, revealing that he knows about his Geass. He asks Kallen, who followed him to Kamine Island, if she wishes to know Zero's identity, then fires at Zero, hitting his mask at just the right angle that it splits in two.
Thus, Suzaku and Kallen discover, once and for all, that the true identity of Zero is none other than Lelouch "Lamperouge" vi Britannia. After confirming that he is, indeed, Zero, Lelouch asks Suzaku to help him save Nunnally. Suzaku, however, refuses to listen to anything the man who killed Euphemia has to say and is determined to kill Lelouch. Lelouch straps a bomb to his chest, set to detonate if his heart stops, and dares Suzaku to shoot him, killing himself and Kallen in the process.
Suzaku declares Lelouch's existence a mistake, and that after he has disposed of him, he would look after Nunnally.
Enraged, Lelouch pulls his gun on Suzaku.
And then, a gunshot...
