After Koduka Chiyo quits her job and spends her time wallowing in self-pity she becomes three months behind on her rent.

Her landlady proposes an unusual solution: perform favors for her in exchange for the owed money – with the first being that the two sleep together.

After a one-night stand, the two women decide to keep the arrangement, slowly growing closer over the coming months.

Written and illustrated by Miyako Miyahara, I Can't Believe I Slept with You!, was serialized in ASCII Media Works' shōnen manga magazine Dengeki Daioh from June 27, 2019, to February 26, 2021.

an overall B rating, remarking of the premise had a lot of legwork to do to bring readers around to the main couple but remarked that they were "nevertheless surprised at just how subtle yet involved the series is in raising some rather realistic questions about non-heteronormative sexual orientations and how society views them.