Meet Katase's younger twin siblings: her sister Fumi, who goes crazy whenever the topic turns to love and romance, and her brother Akira, a laid-back gamer who's always getting caught up in Fumi's schemes. After witnessing Katase's odd behavior during a family visit, Fumi becomes convinced that something is up. Naturally, there's only one possibility that springs to mind for her-that her sister has a boyfriend! The twins take it upon themselves to look into the matter and find out the truth, unbeknownst to Katase and Shinozaki...