When Kazuya returns home, Chizuru, whom he had just parted ways with, comes to visit him.
"I...lost my keys..."
Kazuya is confused and excited at the situation of having Chizuru in his home.
But then the doorbell rings a second time, and a second visitor enters Kazuya's room.

The morning after his night with Ruka, Kazuya unexpectedly runs into Chizuru.
Trying to act naturally, he invites Chizuru to rent him a girl, but she refuses, still misunderstanding his relationship with Ruka.
Desperate to clear up the misunderstanding, Kazuya realizes it's Chizuru's birthday and makes a decision.
"I'll celebrate her birthday properly and somehow clear up the misunderstanding!"