Maggie and her brothers are frustrated by a rainy day which has kept them cooped up inside. To make matters worse, they've been left with an intimidating babysitter, Scary Mary, who puts them to bed without even reading them a story.

Seeking adventure, Maggie and her brothers ask for help from the Magic Map on their bedroom wall and are transported to the bottom of the Pacific Ocean. There they meet Olive the Octopus and her thousands of hatchlings and learn that life for a baby octopus is quite different from their own!