While hanging out at his friend Naoto's house, Shinya remembers that he's promised to hang out with her and decides to go home. However, he realizes that he's left his cell phone behind and rushes back to get it, only to find that Naoto's mother, Akina, and Naoto are lying on each other's skin! Shinya is so taken aback by the sight that he can't take his eyes off it, and when his eyes meet Akina, he panics and runs away, forgetting his cell phone. The next day, when Shinya comes to get his cell phone, Akina starts seducing him, saying, "I want you to keep the fact that we're in a physical relationship a secret."