Anna Koshiro has been friends with two handsome guys, Sou and Hinata, since childhood. She has a crush on Enamoto, a first-year high-schooler, but she has difficulty finding a boyfriend as everyone always wonders about the relationship between Anna and Sou and Hinata. One day, she goes to Sou s house and finds out that Sou has a girlfriend. She is not jealous, but she feels like she has lost him. On the other hand, Sou s girlfriend is upset about how Anna comes into Sou s room so freely and asks Sou not to let Anna into his room again. However, Sou disagrees and ends their relationship. Anna decides to overcome the odds and confesses to her crush. Enamoto accepts, but upon finding out that Anna has a boyfriend, Sou gets upset. On their first date, Anna finds herself in her room with Enamoto. She tells him about something that happened in the past: She once had a chipmunk named Coco, and when it died, Sou and Hinata brought her another chipmunk and telling her it was Coco.
