Lelouch believes Shirley may have discovered his identity as Zero, so he and C.C. pursue her to Narita. Ohgi explores the battlefield of the previous night, discovering the wounded Villetta Nu left for dead out of sight. Lelouch encounters Mao, a young man who also has the power of Geass. Mao uses his mind-reading power to play on Shirley's insecurities, manipulating her into shooting Lelouch, but she falters at the last moment and C.C. sends Mao away temporarily. Since Shirley is being torn apart by grief and guilt, Lelouch uses his Geass to erase her memories of him.

C.C. explains her history with Mao, and how his inability to turn his Geass off drove him insane. An injured Villetta wakes up in Ohgi's apartment and he discovers she has selective amnesia. C.C. leaves Lelouch to take care of Mao herself, but Mao gains the upper hand when he incapacitates her. Lelouch utilizes his intellect to fool Mao and rescue C.C. from him, using the Britannian Police to surround and shoot Mao. Safe on a rooftop away from the scene, Lelouch affirms his contract with her, promising to not fall victim to his power as Mao did.

C.C. departs as a messenger to the Chinese Federation and Milly has a marriage interview with Lloyd Asplund, creator of the Lancelot. Mao returns to kidnap Lelouch's sister, Nunnally, and holds her hostage in the Ashford Academy sewers. Lelouch and Suzaku work together to rescue her, with Suzaku's physical adeptness and the clever use of Lelouch's Geass proving to be beyond Mao's planning. Before he can be arrested, Mao reveals that Suzaku killed his own father, and in return Lelouch silences him with his power. C.C. returns to the campus and finally ends Mao's life as Suzaku crumbles to the ground, confronted with his actions after years of secrecy.