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.
She was the first girlfriend I ever had...
...كانت أوّل حبيبة لي
Sie war meine allererste feste Freundin …
Había sido mi primera novia
en toda la vida…
Era la primera novia
que tenía en mi vida…
C’était ma première nana…
Era la prima ragazza che ho mai avuto...
Ela foi a minha primeira namorada...
Она была первой, 
с кем я встречался за всю свою жизнь!