Eight-year-old Jack and his younger sister Annie use the magic treehouse to travel back to the Middle Ages, where they explore a castle and are helped by a mysterious knight.
Their magic tree house takes Jack and Annie back to retrieve a lost story in ancient Greece, where they witness the original Olympic games and are surprised to find what girls of the time were not allowed to do.
While on a mission to prove to Merlin that they can use magic wisely, Jack and Annie travel to seventeenth-century Venice, Italy, to save the city from disaster.
Their magic tree house takes Jack and Annie deep into the sea, where they meet up with dolphins, sharks, and octopi as they search for the answer to an ancient riddle.
Eight-year-old Jack, his seven-year-old sister, Annie, and Peanut the mouse ride in a tree house to the Amazon rain forests, where they encounter giant ants, flesh-eating piranhas, hungry crocodiles, and wild jaguars.
The magic tree house transports Jack and Annie on a mission to the Ice Age where they encounter Cro-Magnons, cave bears, sabertooth tigers, and woolly mammoths.
Having used their magic tree house to travel to India, where they must get a gift to help free the dog Teddy from a spell, Jack and Annie have adventures involving a tiger and other endangered jungle animals.
The magic treehouse takes Jack and Annie back two thousand years to ancient China where they must find the original copy of an old legend before the Imperial Library is burned down by the evil Dragon King.
The magic treehouse takes Jack and Annie to a moon base in the future, where they continue to search for the fourth thing they need to free their friend Morgan from the magician's spell.