Billy has always lived a hard life with her mother. She has been doing chores and errands since she was seven, because she wants to help her mother. She goes to school and waters her neighbor's small urban garden for a few dollars when she comes home. Billy doesn't have friends because she is just too busy to have fun. She is afraid that if she does have friends, they will just hate her for always leaving them to do chores or errands. One day, as she was watering her neighbor's plants, a small creature jumps inside her pocket. When Billy sees the little creature, she takes care of it. The creature becomes a monster that lives inside her closet. With Billy's new friend, she learns how to have fun and how to be a friend. When Billy gets sick, her monster heals her, but in exchange, her monster gets very weak. Billy does everything to save her monster. What will Billy do to save her only friend? Should she ask her mom for help? What does Billy need to do to save her monster's life?