It is rumored that Touji Seryou, one of the more popular boys at school, would go out with anyone who asks him out on a Monday morning. But on this particular Monday morning, the first person he meets at the school gate is no other than Yuzuru Shino, Seryou's sempai at the archery club. On a whim, and well-aware of Seryou's reputation, Shino asks Seryou to go out with him. Thinking that it will be treated as a joke, they're both guys after all, imagine Shino's surprise when Seryou takes him up on the offer! There is a catch, though. While Seryou does go out with the first girl who asks him out on a Monday morning, the other side of the coin is – by the end of the week, he will break up with that person. In essence, Seryou is a lover with a one-week expiration date. But will Shino prove to be the exception to that rule?