After his parents are kidnapped, timid twelve-year-old Henry York leaves his sheltered Boston life and moves to small-town Kansas, where he and his cousin Henrietta discover and explore hidden doors in his attic room that seem to open onto other worlds.

Fairy realm, bk.3. When her home is threatened by fire, Jessie returns to the magical world of the Realm and visits the mermaids of the Under-Sea to search for a wish-stone.

Omri's birthday present from his best friend, Patrick, isn't what he really wanted. He received other gifts that are much more exciting--a skateboard, a mysterious cupboard from his brother, and, from his mother, a very old key that fits the cupboard's lock. By the end of the day Omri has almost forgotten the three-inch-high Indian Patrick gave him. But just before going to bed, Omri decides to put the Indian in the cupboard. He shuts the door, locks...

Magic Tree House, #37. A Merlin mission. When Merlin is weighed down by sorrows, Jack and Annie travel back to feudal Japan to learn one of the four secrets of happiness.