Company policy brings in an introverted, incompetent intern named Yuki, leaving the husband assigned to train him increasingly frustrated. Worse, Yuki keeps making moves on his wife, Airi. As Airi’s behavior changes day by day, he begins to suspect that the two are having an affair. To discover the truth, he installs a hidden camera, invites Yuki to his home, then claims he has an errand and leaves them alone together.