James, a lonely orphan, is sent to live with his wicked and greedy Aunts Spiker and Sponge. Unwanted and forced to perform their menial chores, the boy dreams about going to New York City--a place, his father once told him, where dreams come true.
Then James meets a mysterious old man who gives him a bag of magical glowing green things (crocodile tongues) and tells him that marvelous things will happen. Racing home, James accidentally spills the contents of the bag at the base of a barren old peach tree.
To his astonishment, a peach instantly appears on the branch and grows and grows until it reaches 20 feet in diameter. Hungry and curious, James sneaks out that evening and takes a bite of the peach. When a glowing tunnel appears, the frightened boy ventures inside and meets Centipede, Earthworm, Ladybug, Glowworm, Grasshopper and Miss Spider.
Rolling out to sea, the giant peach launches its passengers on a series of wildly imaginative adventures with New York City as their final destination.