A Condition Called Love follows Hotaru Hinase, a first-year high school student who has never been in love. When she sees her classmate Hananoi-kun get dumped, she casually offers him an umbrella to shield him from the rain. To her surprise, the next day Hananoi-kun asks her out, beginning an intense relationship where he showers her with affection. This romantic drama explores what it means to love and be loved.