1-2) Kuro x Koi
Ao works at a kindergarten where he has a crush on one of the parents, Haizaki-san. Ao's twin brother, Midori, shows up at his place one day, announcing he's got a new boyfriend. However, knowing Midori’s track record, Ao is worried. After an argument, Midori tells Ao to see for himself and impersonate him on their next date. To Ao’s surprise, he winds up on a date... with his crush!!!
3-4) Shiro x Koi
Continues with Ao's younger twin brother, Midori, and Haizaki Kurose's older brother, Shirase.
5) Aki x Koi
Involves Shirase's son, Aki, and his childhood friend, Akane. Set 8 years later.
Ki x Koi Extra to Aki x Koi.