Summer vacation on an almost private island gives the Aldens a challenge.

When Annie tells him about her missing painting, Nate the Great and his trusted companion, Sam Spade, set out to investigate, gather clues, and solve the mystery.

When the Aldens spend the summer riding on a train, they get to live in a train car once again - this time, they're staying in Caboose No. 777. The number is hard to forget, and indeed, the children meet people at each stop who seem to know it well. It turns out Caboose No. 777 has an unusual past - one that comes with its very own mystery!

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.

Renting a lighthouse is unusual, but even more so is an unfriendly boy's peculiar behavior.

Investigating the mysterious footprints of a home invader who their inventor friend believes is trying to steal his ideas, Hamster Holmes and Dr. Watt work to identify the animal responsible for the footprints before it is too late.

"Eva Wingdale and her class are excited about their trip to Poppy's Pumpkin Farm, where every year, there is one very large, extra special, thank-you pumpkin; but on the second day of the visit the owls find that the Thank-you Pumpkin has gone missing, and the farm animals are in an uproar -- so Eva and the other owls turn detective to solve the mystery of the missing pumpkin." --