Today, I went to a public bath with my sister-in-law.

Yusuke, a Ronin student, lives alone in an apartment without a bath. For Yusuke, who is immersed in studying every day, his brother's wife, Nanako, who sometimes visits him as gifts, is the only solace. One day, Yusuke is invited to a public bath by Nanako. By chance, they end up in the women's bath, and the distance between them grows closer. After that, Nanako, who still doesn't get along well with her brother, begins to invite Yusuke to the public bath, but the guard catches Yusuke in the women's bath again...