Suzaku Kururugi, a Britannian soldier, is shot for disobeying an order to execute his friend and accused terrorist, Lelouch Lamperouge. Fortunately, he survives the attempted execution, finding himself in the Empire's research division when he comes to. It turns out that Suzaku has been chosen as the primary test candidate for the Lancelot, a powerful new combat mech that exponentially increases its user's physical prowess.

Presented with a chance to change the world for the better, he agrees to become the first pilot of the Lancelot. Code Geass: Hankou no Suzaku follows one young man's desperate struggle to protect those dearest to him and defeat Britannia's greatest threat to peace: the cunning, self-proclaimed vigilante Zero.