Mice explore such well-known objects as a telephone, eyeglasses, and a book.

Alexander, a real mouse, wants to be a toy mouse like his friend Willy until he discovers Willy is to be thrown away.

After nibbling an enormous piece of parmesan cheese into the shape of a giant mouse holding a flute, Geraldine hears music for the first time.

Nicolas the mouse sets off to find food for his family and is scooped up by a large bird who takes Nicolas back to her nest, where he finds new friends and tasty berries to take back home.

Unlike the other mice, who are incurious about the wall that has always been part of their world, Tillie is determined to find out what lies on the other side of the wall.