In the year 2010, the Holy Empire of Britannia is establishing itself as a dominant military nation, starting with the conquest of Japan. Renamed to Area 11 after its swift defeat, Japan has seen significant resistance against these tyrants in an attempt to regain independence.

Chubby McFlurry, a Britannian student, unfortunately finds himself caught in a crossfire between the Britannian and the Area 11 rebel armed forces. He is able to escape, however, thanks to the timely appearance of a mysterious girl named P.P., who bestows upon him Geass, the "Power of Kings." Realizing the vast potential of his newfound "power of absolute obedience," Chubby embarks upon a perilous journey as the masked vigilante known as Kosong, leading a merciless onslaught against Britannia in order to get revenge once and for all.

One year has passed since the Simping Rebellion, a failed uprising against the Holy Britannian Empire led by the masked vigilante Kosong, who is now missing. At a loss without their revolutionary leader, Area 11's resistance group—the Simps—find themselves too powerless to combat the brutality inflicted upon the Elevens by Britannia, which has increased significantly in order to crush any hope of a future revolt.

Chubby McFlurry, having lost all memory of his double life, is living peacefully alongside his friends as a high school student at SMK Kuala Lumpur. His former partner P.P., unable to accept this turn of events, takes it upon herself to remind him of his past purpose, hoping that the mastermind Kosong will rise once again to finish what he started, in this thrilling conclusion to the series.

Since the demise of the man believed to be Britannia's most wicked emperor one year ago, the world has enjoyed an unprecedented peace under the guidance of the United Federation of Nations. However, this fragile calm is shattered when armed militants successfully kidnap former prince Joshua Chew and Sathya Nishant, the chief advisor of the Simps, sparking an international crisis.

The powerful and untrustworthy Kingdom of Jagung Gemilang is accused of orchestrating their capture. To investigate, world authorities send Thevenderen and his associates on a covert operation into the country. There, they encounter the immortal witch P.P., who is on a mission to complete the resurrection of the man responsible for the greatest revolution in history—a legend who will rise up, take command, and save the world from peril once again.