After his parents are eaten by a rhinoceros, young James Henry Trotter has to go live with his two mean aunts named Aunt Sponge and Aunt Spiker, who treat him very very badly. Poor James has to live with his aunts for three whole years until one day a mysterious man gives him a bag of magic things. (He tells him they are crocodile tongues.) James is so excited that he starts running back to the house, but when he is underneath an old peach tree in the garden he accidentally slips and spills all the tiny little things and they dig themselves into the roots of the tree.
Suddenly a peach appears on the very tip of the tree and then starts to grow and grow and doesn't stop until it is as big as a house! The aunts are so excited about this that instead of immediately eating pieces off the peach they start charging people to see the peach. After everyone has left they force James to pick up all the litter that the people left behind. Poor James is left all alone in the dark! For no particular reason, James walks up to the peach and starts touching it. He notices that there is a rather large hole in the peach. He crawls in, and the hole becomes a tunnel. He keeps on crawling until he reaches the center of the peach. He meets seven oversized insects who turn out to have swallowed some of the tiny little things that James had spilled. When the stem snips off (with some help, of course), the peach rolls off and the eight travellers embark on the adventure of a lifetime!