Uno Masanao, a 19-year-old student of a university of the arts, works part-time at a convenience store in Tokyo. Every night, a mysterious older woman Gota Mika comes to this convenience store and only buys sauce. He falls in love with her and takes to calling her Sauce-san. One day, the two of them form a connection when Masanao sends Mika home after she is chased by a molester and they go on to date despite their 10-year age gap. However, Mika’s trauma somehow rears its head as a result of her tragic past. As her past is gradually revealed, it offers glimpses of the unexpected truth and their relationship eventually cracks...