In this story inspired by Jules Verne's "20,000 Leagues Under the Sea," Ana Dakkar, a freshman at Harding-Pencroft Academy, a five-year high school that graduates the best marine scientists, naval warriors, navigators, and underwater explorers in the world, makes astounding discoveries about her heritage and puts her leadership skills to the test against deadly enemies from a rival school.

The Alden children meet Mike Wood and a strange chain of events begins. Mike's house is mysteriously burned down, a man in a blue hat appears, and the Alden's uranium mine is in danger of being sabotaged. The four children solve the mystery.

Benny's friend accompanies the Aldens to the South Seas for a vacation on a supposedly deserted island where they find an unusual mystery.

The Aldens search for carousel horses that have disappeared from an amusement park.

Twelve-year-old Crow has lived her entire life on a tiny, isolated piece of the starkly beautiful Elizabeth Islands in Massachusetts. Abandoned and set adrift in a small boat when she was just hours old, Crow's only companions are Osh, the man who rescued and raised her, and Miss Maggie, their fierce and affectionate neighbor across the sandbar. Crow has always been curious about the world around her, but it isn't until the night a mysterious fire...

At an old library, the Alden children discover a boy who needs their help and a stranger who is after a valuable object they found in the library.

On the island, everything is perfect. The sun rises in a sky filled with dancing shapes; the wind, water, and trees shelter and protect those who live there; when the nine children go to sleep in their cabins, it is with full stomachs and joy in their hearts. And only one thing ever changes: on that day, each year, when a boat appears from the mist upon the ocean carrying one young child to join them -- and taking the eldest one away, never to be...

The Alden family rents a houseboat to drift down the river, and encounters a mystery in the little towns along the river, involving a fast black car.

Six children help solve the mystery of a missing spyglass that has kept two brothers feuding for years.

While visiting a friend of their grandfather's on Sullivan's Island, off the coast of South Carolina near Charleston, the Boxcar Children encounter mysterious activities related to rumors of a buried pirate treasure.