The adventures of the four Alden children as they investigate a mystery that took place in the yellow house on Surprise Island many years before.

A hard-bitten former search-and-rescue dog helps solve a complicated missing chicken case.

Because they do not want to be separated, four orphaned children run away and live in an old abandoned boxcar

When the squirrel Tail comes barreling into the chicken coop ranting about a round, shiny, green, big, scary thing in the yard, Dirt, Sweetie, Poppy, and Sugar investigate this strange object.

When priceless antiques begin to disappear from Squire Grizzly's mansion, the ghost of his ancestor Bad Bart is suspected.

Dunkum follows a trail of secret coded messages to find his missing autographed basketball.

Nate the Great, the junior sleuth, and his faithful dog, Sludge, track down a friend's missing stamp, the one with the picture of a dinosaur.

Cam uses her photographic memory and her brain to solve two mysteries at the beach, involving a missing mother and a missing set of papers.

The Aldens are excited to visit a deserted South Seas island. But soon they discover clues that they are not alone. Is someone watching them?

Dink Duncan and his two friends investigate the apparent kidnapping of famous mystery author Wallis Wallace.