A farm cat who doesn't want to catch mice keeps a family of them as pets in the barn; but then he is given away to a townswoman and acquires a new perspective.
Three mice brothers, ignoring the class system separating the four clans of rodents in their farmhouse, befriend a lower class mouse and form a team to fight cats.
After many unsuccessful attempts, lonely mouse farmer Charlie Muffin finally breeds a green mouse, finds true love, and wins the Best of Show at the Grand Mouse Championship Show.