Returning from their internships, the students of Class 1-A are immediately thrown into more training by their homeroom teacher, Shouta Aizawa. For this exercise, the class will be joining four students from Isamu Academy High School to compete in a survival game. Split up into groups of four, students must either eliminate each other or stay hidden until time runs out to win. The training also acts as a reunion between Tsuyu Asui and her friend from middle school, Habuko Mongoose. However, not all the students from Isamu are friendly—Katsuki Bakugou almost instantly picks a fight with Romero Fujimi. The conflict between the two leads Romero to angrily release his Quirk, a gas which zombifies anyone it comes in contact with. How will the remaining students deal with the situation after most of the people around them turn into zombies?