"That person only comes on the second and fourth Tuesdays." Ritsu, who works at a coffee shop, is in love with a customer. A strong appearance that does not match his personality. Their age and occupation are unknown, but still a person she's interested in. "I want to know more about that person." A love story that begins with "I don't know anything" that you cannot find with a dating app. A beautiful waitress and a mysterious man. A pure love story between adults begins.