Koiro is a quiet and plain sister-in-law.She was expressionless at home, wearing no make-up and glasses, but one morning she showed up with a little make-up on.A younger brother worries about his older sister, and small changes accumulate in order to respond to that.My younger brother can't stand it anymore and confesses that he's loved him for a long time.The older sister refuses because they are siblings, but the two of them rub their crotches with the promise that they will end it with only bare legs.Although it ends once, the two of them can't forget the excitement of that time, and the two of them end up having sex.Once they have sex, they can't stop and their bodies overlap each other over and over again.
