Ragweed, a young country mouse, leaves his family and travels to the big city, where he finds excitement and danger and sees cats for the first time.

Poppy, accompanied by her troublesome son Junior, his skunk friend, and Uncle Ereth the porcupine, responds to a summons to return to her ancestral home, Gray House, to save the mice there from destruction by a bulldozer.

When their home next to a brook is destroyed by beavers, a large family of golden mice is aided by Poppy the deer mouse and her grumpy porcupine friend, who in the process forges a relationship with the son he had abandoned.