The Alden children find an unusual mystery when they spend a vacation on a supposedly deserted South Seas Island.

Grandpa Alden and the Alden children encounter danger, excitement, adventure, and mystery in a quiet island fishing village.

While on bicycle trip to their aunt's farm, the four Aldens help solve a mystery.

Four orphans take shelter in an old boxcar during a storm, and, determined to make it their own, they turn it into a safe, cozy home.

Violet and Jessie begin an adventure when they journey to Centerville to keep Aunt Jane company on the family ranch.

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.

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.

While on a cruise with their grandfather, the Alden children help discover who is behind the mysterious troubles of the ship--disconnected phone lines, engine trouble, a man overboard--and still have fun sightseeing, eating, and swimming.

When the Alden children accompany their grandfather to the Snow Haven Lodge, a series of odd occurrences threaten to disrupt the annual winter games.

The Alden children have another mystery to solve when they visit a castle and must figure out which of the guests has stolen the Stradivarius violin.