Better the Devil You Know Than the Devil You Don't Know

High school student Akiharu Abe is working through his summer at his family's temple. By chance, he happens to try a little charm that his deceased mother taught him when he was young. Press against the star-shaped mark on his wrist and repeat her words...

But to his surprise, this time, something actually happens! He opens a portal and summons...Satan?! Having been relying on a contract that grants one party the power of "the child of a god" in exchange for doing housework, Satan is now a hopeless demon who doesn't even know the first thing about taking care of himself. Not only is Akiharu being pulled left and right to help this hopeless demon, Satan even asks Akiharu to help him replenish his power...through a French kiss?!

This is a love story about the weirdest roommates: a high school descendant of an onmyouji, and a buff, innocent lord of the demon realm.