After forgetting to hand in his science report, Sera heads for the faculty room to give it to his teacher, Kurata. But as he peers through the room's window, Sera catches his teacher alone with Sasaoka, another male student. Instead of interrupting, Sera continues to watch curiously as the two engage in indecent acts. Being a witness to their shocking secret relationship, Sera decides to confront Sasaoka about it, who seems more than receptive to the former's advances.

[Written by MAL Rewrite]