James Henry Trotter is a boy who lives happily with his parents in a house by the sea in the south of England. Unfortunately, when he is four years old, an oddly carnivorous raging rhinoceros escapes from the London Zoo and eats James' parents whilst they are on a shopping trip in the capital. He ends up living with his two cruel aunts, Spiker and Sponge. Instead of caring for him, they physically and verbally abuse him, isolate him in their ramshackle hilltop house and garden, dole out sadistic punishments for the smallest infractions, force him to sleep on bare floorboards in a prison cell-like room, and force him to do heavy chores most of the time that they can't be bothered to do themselves (they also do not call him by his real name, but insults like "you disgusting little beast" or "you miserable creature").
One day, after James has been living with his aunts for three years, he meets a mysterious man who gives him a bag of magical crystals, instructing James to use them in a potion that would change his life for the better. While returning home, James stumbles and spills the bag on the ground, losing the crystals as they dig themselves underground. A nearby barren peach tree, in turn, produces a single peach which soon grows to the size of a house. Spiker and Sponge build a fence around it and earn money by selling viewing tickets to tourists; James is locked in the house, only able to see the peach and the crowds through the bars of his bedroom window.
After the tourists have gone, James is assigned to clean the rubbish around the peach and finds a hole inside it. He crawls in, through a tunnel, and he finds himself in a room, in the enlarged peach pit. There, he meets Centipede, Miss Spider, Old Green Grasshopper, Earthworm, Ladybug, Glowworm, and Silkworm who become his friends.
The next day, Centipede cuts the stem of the peach, causing it to roll away and crush James' aunts. It reaches the sea and is surrounded by ravenous sharks. James uses Miss Spider and Silkworm to make threads, while Earthworm is used as bait and draws 501 seagulls[7] to the peach, whereupon the threads are tied on their necks. The peach is lifted off the water. High above the clouds, the peach encounters the Cloud-Men, who are portrayed as responsible for weather phenomena like hailstorms and rainbows. Centipede mocks the Cloud-Men, who throw things at the group until they get clear.
Later, James realizes that the group has reached New York City. The wing of a passing plane severs the strings, and the falling peach lands on the spire of the Empire State Building. It is mistaken for a bomb at first, resulting in the arrival of police and firemen. Calming the crowd, James tells his story, and becomes friends with many children in New York; they eat the peach and James and his friends get their own jobs, now residing in Central Park, in the pit of the peach.
