While staying at the Winding River Lodge, the Alden siblings investigate tales of a zombie haunting a lake in the woods.

When the Alden children go camping on Blizzard Mountain, a place said to be inhabited by a ghost looking for buried treasure, they begin to think someone or something is trying to scare them off.

The Aldens investigate the rumors of ghosts, disappearing props and a haunted seat in the Trap-Door Theater.

When the Alden siblings visit their grandfather's friend in an apartment building, they begin to wonder about the many mysterious events that keep happening on the thirteenth floor of that building.

A series of practical jokes at a restored nineteenth-century farmhouse makes the Aldens wonder if the ghost of its builder is at work.

The Aldens' neighbor, Lina, thinks there's treasure hidden in her attic, and she wants the Aldens to help her find it. Of course, the children are eager to help search — but it appears they aren't the only ones looking for the treasure. Can the Boxcar Children discover the treasure in the attic . . . before someone else finds it first?

"One day in the park, the Aldens' dog, Watch, comes across a mysterious box with a note inside. 'Congratulations!' the note says. 'You've found it!' The box is part of a game called Geocaching. Soon, Henry, Jessie, Violet, and Benny are searching all over town for hidden boxes and making friends with other kids in the geocaching club. But is one of the club members a thief?" -- p. [4] of cover.

The Aldens accompany their grandfather to his class reunion and investigate the possibility of a buried Civil War treasure, and of a ghost in the bell tower, at Goldwin University.

The Alden children hunt for their late grandmother's necklace that has been missing for years.

At the same time that the Alden children's efforts to raise money for a new hospital wing are being sabotaged by nasty tricks, they find their attempts to befriend the new girl Beth frustrated by her strange behavior.