When Souta takes over the backwashing duties at his family’s bathhouse, he never expects to end up scrubbing the back of Aoi — the tsundere classmate he constantly clashes with. Disguised and unrecognized, he indulges in some risqué “slimming massage” revenge on her sensitive body. But the more he touches her, the more he discovers Aoi’s hidden crush on him… and she soon realizes the mysterious washer is actually Souta.

What starts as a simple prank turns into a passionate, clumsy romance filled with sauna heat, hidden shower trysts, jealousy, confessions, and plenty of skin-on-skin action. With the volleyball team captain Mei stirring the pot and rival Takazuki adding tension, the two awkward teens navigate their growing feelings while trying (and failing) to keep things secret. Equal parts erotic comedy and sweet coming-of-age love story, this hot spring of youth bubbles over with desire, embarrassment, and genuine affection.