Satou is a member of the Special Assault Team mobilised by the Diclonius Research Institute to find and eliminate the rogue Lucy. He has the misfortune to be partnered up with the sociopathic commando Bando when the group arrive on the beach at Kamakura. The pair find Lucy (currently in her Nyu personality) and Bando is irritated by the girl's docile behaviour, having been briefed that she was supposed to be a vicious killer. Bando tries to urge Nyu into attacking him and Satou tries to radio the rest of the squad, but then Bando purposefully smashes Satou's radio. After failing to provoke Nyu, Bando orders Satou to shoot her. Satou is unconvinced that they have the right target but prepares to follow the order regardless. Just before he pulls the trigger, Lucy reawakens and tears a gaping hole in Satou's torso before chopping off one of his arms, then his head.