Jilted and heartbroken, 20-year-old Kinoshita Kazuya turns to Diamond, a Rent-A-Girlfriend app that leads him to a fateful encounter with Mizuhara Chizuru, one of the talents on offer.

Kazuya barely has time to deal with the fallout of the situation in the pub before the gang heads off on a short trip to Izu, where they run into someone unexpected.

While Kazuya desperately tries to get Ruka to promise she won’t reveal his secret, she tells him her own.

Chizuru and Mami go on an awkward rental date unaware that Kazuya has seen them together. How can Chizuru handle this situation?

Kazuya tries to clear the misunderstanding Chizuru is under, all while enlisting Sumi's help to get her a fitting birthday present.

When Nagomi hears that Chizuru's birthday has already passed, she decides to throw a combined party for both her and Kazuya, and she refuses to take no for an answer!

Kazuya and Chizuru have decided to make a movie together so that Granny Sayuri can see it. That's all well and good, but now they have to sit down and work out all the details.

With the momentum of the crowdfunding campaign stalling, Kazuya must turn to Mini, who happens to be an expert on the matter!

It's Ruka's birthday, and Kazuya has to stay true to his word and grant her anything she desires. But what does she want, really?

Seeing Chizuru overcome with grief, Kazuya decides to give her an outlet and sees the ensuing moment as a big change in their relationship.