Two teenagers trade unrequited love like a deal struck in hell. They use each other's bodies to practice for people who will never want them back. The show doesn't flinch when their arrangement fractures into something uglier and more honest than either of them expected.

Hanabi has quietly loved her older friend Narumi for years. Then he becomes her homeroom teacher, and her world gets worse: he's clearly smitten with Akane, the music teacher. She then discovers that another student, Mugi, carries the same hopeless feelings for Akane, who once tutored him. If the people they want are out of reach, why not use each other? Not romance. Not love. Just two lonely people offering physical closeness as a stand-in for someone else. To everyone at school, Hanabi and Mugi look like an ideal couple, but only they know the secret behind it and the ache each of them is trying to dull.