Himeji Wakaba is a fifth-grade elementary school student who possesses the ability to see things that others cannot. These entities are mostly frightening evil spirits, and they tend to harm people close to her. Consequently, Wakaba has no friends and rarely smiles. On a few occasions, she has brought stray animals home, but her parents refused to let her keep them. However, concerned about their sad and creepy daughter, they decide one day that they will allow her to keep whatever she brings home next. The next creature she brings home is a pink monster called "Pupipo," and her parents honor their decision, allowing her to keep it. No one is quite sure what Pupipo is, but it protects Wakaba from the other entities she sees. Pupipo also helps Wakaba befriend an occult-obsessed transfer student and resolve issues with bullying. Wakaba's life is a much better place with her pet pink monster!