Koi ga Shitai x3 ("Where is Love?" or "I Want to be in Love") is a character driven story that examines the relationships and bonds that six random people thrown together at one moment share with one another, and how that bond develops over the course of the series.

The seven main characters are named after the colors of the rainbow to correspond with the theme song, "Rainbow Connection" by the Carpenters. First, there is Akai Ryosuke (Red), a high school teacher that is having relationship problems with his fiancee a few days before the wedding; Second, there is Hada Ai (Indigo), a woman who feels like she's drifting aimlessly through the world, latching on to different men so she feels less lonely; Third, there is Nagashima Mikan (Orange), a socially awkward hotel worker searching for love; Fourth, there is Shimura Ichiro (Purple), an author playboy that holds a secret that prevents him from getting close to others; Fifth, there is Midorikawa Bunpei (Green), a down-on-his-luck gyuudon (beef-bowl) restaurant manager; Sixth, there is Aoshima Wataru (Blue), a busy high school student searching for a partner; and lastly, there is Kouda Orie (Yellow), a housewife that is in a loveless marriage.

One fateful day, they all meet at Bunpei's gyuudon-ya and the bonds of fate begin to tighten, as we soon discover all of the characters are related in one way or another. As in the title, each of these characters are searching for love, but will they find it in the end?