Shinozaki Sumire finds herself in a very difficult situation, without money and people who can help her, after her mother suddenly disappears. In desperation, she decides to turn to the "Free Frinds" forum to earn some money. So she meets Kaito-kun and soon realizes that he is not just a new acquaintance. Kaito works as a teacher at the Minatohashi Higashi Academy and he considers his only drawback to be the inability to form meaningful intimate relationships (in short, he does not stick to relationships with girls and everyone leaves him) .... In general, he makes everything simpler and satisfies his needs through purchased love. Therefore, he is a rather frequent visitor to the forum "free forts ". Thanks to which he can meet, get acquainted with various girls, have sex and at the end just pay them for time. Having met Sumir, he understands that she is not just another girl for one night. The violets who loves our heroine reminded Kaito of his own sister with whom he was separated in childhood when his parents divorced. They like the past and they seem to know each other for a very long time ...