When thirteen-year-olds Jonah and Chip, who are both adopted, learn they were discovered on a plane that appeared out of nowhere, full of babies with no adults on board, they realize that they have uncovered a mystery involving time travel and two opposing forces, each trying to repair the fabric of time.

Their magic tree house takes Jack and Annie back to a monastery in medieval Ireland, where they try to retrieve a lost book while being menaced by Viking raiders.

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.

"Ashley can't get comfortable in her family's new apartment.  Sometimes she hears a child crying, though no one is near, and everything she does--especially going into the garden or playing with a mysterious white cat--upsets the irritable landlady.  The discovery of an old doll buried in the forbidden garden starts Ashley on a quest to find out who it belonged to, and why it was buried.  The landlady claims the doll is hers.  But an eerie encounter...

The magic tree house takes Jack and Annie to San Francisco in 1906, in time for them to experience one of the biggest earthquakes the United States had ever known.

Jack and Annie are transported by their magic tree house to the time of the Civil War where they meet Clara Barton.

When eight-year-old Jack and his seven-year-old sister, Annie, join a group of nineteenth-century explorers aboard the H.M.S. Challenger, they learn about the ocean, solve the mystery of its fabled sea monster, and gain compassion for their fellow creatures.

Jack and Annie travel in their magic tree house back to a Hawaiian island of long ago where they make friends, learn how to surf, and encounter a tsunami.

Joe, Fred, and Sam demonstrate some of their favorite professional wrestling moves, including the "Time Warp Trio Blind Ninja Smackdown," when they're transported to ancient Rome and forced to fight as gladiators in the Colosseum.