James meets a mysterious man with a bag of magic green "crocodile tongues", which he gives to James to make his life better, as he is currently living with his two cruel aunts, Spiker and Sponge. The soldier explains that these magical "tongues" are "boiled in the skull of a dead witch for 20 days and 20 nights. Add the fingers of a young monkey, the gizzard of a pig, the beak of a parrot, and three spoonfuls of sugar. Stew for a week, and then let the moon do the rest". The soldier then tells James that "marvelous things will happen" if he accepts the "tongues", to which James agrees. The soldier then warns him not to lose the "crocodile tongues", or else "they'll work their magic on whoever or whatever they meet first", and disappears. When James returns to his aunts' house, he trips, and the "tongues" escape into the ground. Shortly after, the magic from the "tongues" causes a peach on a withered old tree to grow to giant size. Later, when he finds the same bag, he comes across one that hasn't escaped, and it grants him its magic by jumping into the piece of peach he ate, causing him to transform into a stop-motion animated character. James sneaks inside the peach and finds a group of bugs who have become human-like from the magic of said "tongues". When the peach lands on top of the Empire State Building in New York City, James coughs out the crocodile tongue he swallowed earlier and transforms back to his normal self. At the end of the story, the old man who is revealed to be the narrator catches the remaining "tongue" and winks.
When James Henry Trotter, Mr. Centipede and Miss Spider dive underwater, the Crocodile Tongues presumes to have the ability to help them breath and talk underwater.