Horie Mana leads a fulfilling life as a sales clerk at Tomiya Corporation. Mana is interested in her coworker Hashii Tsubasa, but her reserved personality makes her content just by looking at him from afar. One day, Mana's high school classmate, Honda Ai, shares that she saw their other classmate, Takato Hino. Hino was Mana's only close friend and they had lost contact since graduation. Then Mana fatefully runs into Hino and welcomes Hino to her house after learning that she has no place to stay after getting a divorce. Adapted from the manga series "Shinyu wa Akujo" (親友は悪女) by Wada Yoriko (和田依子).