An earnest little demon ends up in dire straits as he's summoned by a human with a libido rivaling that of a devil.

A college student Satoru Shiiyama had a crush on Jun Mariya ever since middle school, but the object of his affections dies in an accident. In the midst of his grieving, Satoru accidentally summons a demon and gets a once-in-a-lifetime offer: "In return for your life span, I'll grant you a wish." Having lost all hope, Satoru agrees. Just what is the wish that he made...?
This is a heart-warming(?) love story between a selfish, lustful guy and an honest, cute little demon.