After our MC got in a relationship with Mizue, the sexy older girl living next door, something bad ought to happen to him to balance it out, right? And indeed, his heater dies in the middle of the winter.
But then Mizue invites him to sleep in her apartment for the week until the heater gets fixed. She jumps on him the very first night and what follows is a whole week filled with non-stop lovey-dovey lovemaking in every room her apartment has. She even buys a cosplay outfit to wear for the occasion. It’s, of course, a succubus costume because she’s really planning on wringing the MC dry~