During a routine training exercise, Class 1-A and Class 1-B are suddenly pulled through a mysterious portal caused by a Quirk accident. Expecting danger, they prepare for battle—only to discover something impossible. In this strange world, heroes are villains, villains are heroes, and everything they know has been reversed. Now face-to-face with their alternate selves, the students must uncover the truth behind this twisted reality before both worlds collide. But one question remains… Who will notice the intruders first?