A demon arrives to devour a human soul and accidentally catches feelings instead. The joke is that Kanan has zero romantic experience, so every date becomes a collision between demonic hunger and genuine confusion about why she'd rather be around this guy than eat him. She keeps trying to seduce him the way demons actually would, and it keeps backfiring into something real, and neither of them knows how to stop.

Kanan is a demon who comes to the human world and poses as a high school student so she can feed on the souls of young people. She picks out an unremarkable boy named Youji Kyougi as her first target. Just as she moves in to claim him, things go sideways, and instead of eating his soul she ends up bound to him in a romantic contract. Kanan has lived for thousands of years without ever being in love, and the ordinary milestones of a teenage relationship scare her more than any hunt. Awkward dates, clumsy attempts at holding hands and emotions she cannot put a name to leave the once-proud demon flustered again and again. The result is a supernatural romantic comedy with ecchi and fantasy touches, built on a pure-hearted demon's first love and the boy who was meant to be her meal.