Rudolf is a housecat who lives a pampered life, with a young girl named Rie and the rest of her family. When Rudolf attempts to follow Rie on an errand, however, he ends up in the back of a truck that takes him far away from his home—as well as everything he has ever known.

Luckily for Rudolf, he soon meets Ippaiattena, a stray cat who teaches Rudolf the ways of survival. Ippaiattena even shares his greatest skill, the ability to read and write Japanese, which allows him to understand the complexity of the world in a way that few animals can. Armed with this new knowledge, Rudolf continues to look for a way to cross Japan and return to his doting family.

Rudolf to Ippaiattena adapts Hiroshi Saitou's 1987 children's book of the same name, for which he won the 27th Kodansha Award for New Writers of Children's Literature.