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

Relates the exploits of the four Alden children as they locate a missing man. The Boxcar children are determined to solve the mystery that surrounds an old yellow house on their grandfather's property. Strange things have happened in that house where long ago a man disappeared.

The children are spending the summer on their own private island but there is a mysterious stranger on the island.

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

The Alden children, isolated in a storm at a small bus station, are led into a mystery centering on a polluted river.

While spending two days touring a zoo to see the baby animals, the four Alden children, aged six to fourteen, help catch an escaped monkey, participate in a photography contest, and investigate a missing camera.

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.

The classic story of four orphaned siblings, Henry, Jessie, Violet, and Benny, who find an abandoned boxcar in the forest and decide to make it their home--

The children, who are spending the summer in a lighthouse on the New England coast, are disturbed by a mysterious woman walking the lighthouse grounds. Jessie's dog Watch wakes up growling almost every evening at midnight, and Henry finds a puzzling note in the sand.