James Henry Trotter is a boy who lives with his parents in a house by the sea happily. Unfortunately, when he is four years old, an escaped rhinoceros from the zoo kills James’ parents, forcing him to live with his two aunts, Spiker and Sponge, who are terrible bullies. Instead of caring for him, they treat him badly, feed him improperly and force him to sleep on bare floorboards.
After James had been living with his aunts for three years, he meets a mysterious man who gives him green beans and says that if he would drink it his life would be full of adventures. While going to his home he falls and the beans spill on a peach tree which produces a single peach and it grows to the size of a house. Spiker and Sponge build fences around it and earn money by selling tickets to tourists and they get to see the peach. But James is locked in his house and sees the peach through the bars of the window.
James is assigned to clean the rubbish and finds a tunnel in the peach and goes through it and meets Centipede, Miss Spider, Old Green Grasshopper, Earthworm, Ladybird, Glowworm, and Silkworm who become his friends.
The next day, Centipede cuts the stem of the peach, causing it to roll down and kill James’ aunts. It reaches the sea where sharks surround it. James uses Miss Spider and Silkworm to make threads and Earthworm as bait and draws 501 seagulls near the peach and ties the threads on their necks. The peach is lifted off the water and Centipede falls down but is later rescued by James. The peach goes into the clouds and meet cloudmen demons. Then Centipede mocks them which makes them angry and they start throwing hailstones at the peach. James manages to pull the peach down on the lower part of the sky and realises that they have reached New York City. People think it was a bomb and warn the others to evacuate.
Then officers and firemen arrive and see the peach and some faint. Then James comes and tells the whole story and becomes friends with many children in New York and they eat the peach and James and his friends get their own jobs.