Haruomi Saito is a young man who moves from his hometown to Tokyo to attend a university. He begins to live in a lodging place that charges the low price of 10,000 yen per month. On his first day there, he meets a beautiful girl named Kokono. While making conversation with her, Haruomi Saito’s face blushes. He suffers from erythromania, which causes him to blush often. Haruomi Saito is excited to live with a such beautiful girl, but he soon discovers that Kokono is actually a man.