While staying at an eighteenth-century inn in Vermont, the Boxcar children become curious about the mysterious "accidents" that keep plaguing the owners.

The Alden siblings continue their mission to return lost artifacts around the world by visiting the Great Wall of China and an elephant reserve in Thailand, among other sites, but halfway around the world trouble seems closer than ever.

Following clues provided by the secretive Reddimus Society, the four Alden siblings travel to a dingo sanctuary in Australia and to Shakleton's hut in Antarctica to deliver the fifth and sixth artifacts, and then they work to unmask the traitor traveling with them.

"Henry, Jessie, Violet, and Benny used to live in a boxcar. Now they have adventures everywhere they go. At a lighthouse, the children find a mystery in the night!"

The Aldens arrive in Egypt, but the agent they're supposed to meet has gone missing! With the help of a puzzle in a papyrus scroll, they figure out their next mission--to deliver a tiny ancient pharaoh statue to an archaeologist at the Pyramids! Along the way, they outwit a thief who tries to steal all the treasures. Their next mission is to England, to return one of the "crown jewels of Stonehenge," but someone is following them! Could it be someone...

The Alden children start out on a one-day mountain climbing excursion that becomes very exciting. They unearth some mysteries and some treasure and have a good time in the process.

The adventures of the Alden family as they ride across country in a caboose that has a strange history--or is it a mystery.

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

"The Aldens are visiting Port Elizabeth when a bad storm rolls in, knocking out the power--and leaving behind a mystery! Can the powered-down Aldens figure out what's going on?" -- Page [4] cover.

Henry, Jessie, Violet, and Benny used to live alone in a boxcar. Now they have a home with their grandfather, and they're exploring a haunted house!