Dinosaurs are a common sight in the town where Neneko, a manga artist in her 30s, lives. Some are kept as pets, and some are stray. One day, while living with her younger sister Fuki, her father, who rarely comes home, arrives. Her father is going to Mongolia to excavate fossils, so he has come to leave his younger sister, Yorika, who's from a different mother, in Neneko's care. Neneko is against the idea, but is dazzled by the money he is given and decides to take her in. At that moment, a dinosaur arrives along with Yorika.