An older brother, who works at a foreign-funded financial institution, and his younger sister, who works at a local mobile phone shop, secretly make love in the bathroom of their home, where their parents live. (Ayase Ten START-233)

They had been in love for eight years and dating for seven. After the older brother left home, they met every three months. Considering their reputation and future, they decided to separate for two years. They tried to find other partners, but this was obviously impossible for this brother and sister whose romantic relationships were illogical. They agreed to live together in Tokyo.