In a world plagued by monstrous beings known as the 'enemies of humanity,' teenagers with extraordinary abilities known as 'Talents' gather on a remote island to train in combating these threats. Nanao Nakajima stands out among his peers for lacking a Talent, enduring bullying yet persevering in his training. The arrival of two enigmatic transfer students, Kyouya Onodera and Nana Hiiragi, sparks a shift in dynamics within the class. As unity amongst the students strengthens, a series of puzzling vanishings jeopardizes the very fabric of their group.