It's a story about the relation between Nagisa and Kayano after their graduation. In this story Koro Sensei survives and the identity of the students remain a secret, or so do they think. A sudden blackmail comes up putting everything they had in threat, how will they fight against it? How will this influence Nagisa and Kayanos relationship?

Nagisa came back from his 4 year studies in America. Waking up because of his jetlag, he met someone he had missed the most in his old classroom.