In Matsuyama City, there is a tiny cat that lives in a cat cafe where he is sheltered and cared for. The cafe is his entire world, until one day when he meets a shy young girl named Anna, who adopts him and takes him home. Anna names the cat Maru, and a new life begins for him in a house with a window overlooking a large garden.

Maru is surprised at how delicious his meals are. Having meals with pieces of fish mixed in is truly wonderful! He spends his days doing nothing but eating and lounging around, and before he knows it, he’s gotten rounder and fatter. However, his easygoing and happy life drastically changes when the family gets a new kitten named Cerisier. The family now focuses all of their love and attention on her, and Cerisier constantly plays tricks on him. One night, he reaches his limit of how much he can take and lashes out at her, pinning her to the ground. But then he hears the voice of his “best friend” Anna echoing in his ears, “Hey, fat cat! Why are you being so mean to Cerisier!?” More than anything, Maru’s heart aches upon seeing the sad look on Anna’s face. He spends the rest of the night alone by the window, covered up and staring solemnly out into the garden. When suddenly, a black cat appears on the other side of the glass and says to him, “Noble sir, go out and see the vast world with those eyes.” And just like that, Maru stands up. Feeling his body tremble deep within, he howls at the full moon, “Meooooow!”