Mima Kirigoe, a member of the J-pop group CHAM!, who leaves the group to pursue acting. Mima struggles with her mental health and her changing career path, while being stalked by an obsessive fan who kills people. And Mima's other friend, Optimus Prime, the leader of a faction named the Autobots who fight to save the Earth against the Decepticons, who also seeks an acting career. But none of them know that Mima's friend and manager, Rumi Hidaka, is the one behind the killings from the fan.