Yuta Gazuma, a high school student who has never experienced her first love. I don’t know if I’m in love, but my classmate, Nodoka Kanzaki, is anxious. Is this love !? Meanwhile, his younger sister, Yoru, who dreams of summoning the devil, was performing the summoning ritual as usual. At that time, the magic circle suddenly shines, and a girl comes down from the sky … She’s a demon Lars from the demon world, and she offers a contract with Yuta …!?