Tatsuya is visiting his aunt Ria's house during summer vacation. Ever since he was a child, Tatsuya had admired the kind and beautiful Ria, but now that he has grown up, those feelings have changed into those of a grown man towards a woman. However, his aunt has a husband. Tatsuya is helpless and keeps his feelings to himself... but then, whether she knows how Tatsuya feels or not, Ria makes an unexpected suggestion. "Shall we take a bath together like we used to?"