"Why don't you sleep in this room?" — Kazuya ends up spending the night in the same room as Chizuru at a hot spring inn.
Kazuya's heart is racing, but he suddenly wonders what Chizuru thinks of him.
A few days later, Kazuya's friend Kuribayashi tells him that he has a girlfriend, and in the course of the conversation, they decide to go on a double date with Chizuru.
On the day of the date, Kuribayashi introduces him to a stunningly beautiful girl, Sarashina Ruka. It turns out she was the girl Kazuya had bumped into by chance on the street.

Kazuya, who had started a (temporary) relationship with Ruka, lived in constant fear that his relationship with Chizuru might be exposed at any moment.
Winter arrived without him being able to see Chizuru, and it was Christmas Day.
On his way home from the bank, Kazuya spotted Chizuru, who was dressed more stylishly than usual, and began to consider a "cruel possibility."
"Does 'Rental Girlfriend Mizuhara Chizuru' have a boyfriend...?"