The anime follows a cat named Maru, who is taken in by a girl called Anna from a shelter in Matsuyama. The family loves and feeds him well, so Maru grows plumper each day, spending most of his time perched by the window watching the garden outside. When a new cat named Cerisier arrives and receives the family's affection, Maru feels jealousy. During a quarrel with Cerisier, Maru is hurt by the family's harsh words; following another cat's counsel, he decides to leave and explore the world and discovers new adventures beyond the city limits.
