Takaya Saiki, a boy people are quick to misjudge, turns up a flask and lets out Lilim, a succubus who feeds on life energy through kisses. The first one knocks him unconscious. She flies off after more, then comes back declaring his energy the tastiest she has tried, and Takaya's parents take her in as a live-in girlfriend of sorts. He spends the rest of this two-volume comedy keeping house and school running with a hungry devil attached to him.