Mercenary adventurer Theo Aspel is tragically weak, leaving him no choice but to repeatedly joins various parties--only to get kicked out. In order to get stronger, he succeeds at summoning a demon that will grant him a wish. But the minute he sees her, his wish to get stronger flies straight out the window. This devil, who hadn't been summoned in many years declares: "I will grant your wish, but you must give me something precious to you."
Theo stutters out a reply: "W--will you marry me?"
The devil is stunned to say the least, but grants his wish, making them husband and wife. They embark on a happy married life together, causing quite a stir around them along the way. This is a story of a boy and a girl that's a just a tiny smidge dirty.