The Aldens visit Grandfather's friend at the Ogopogo Retreat and aided by puzzling clues, embark on a treasure hunt to prevent the retreat from being sold.

Alice is running for mayor, and someone is using deception to try and beat her, so it's up to the Boxcar children to find out who's behind the dirty tricks.

The Aldens visit the town of Sleepy Hollow, where it seems that the Headless Horseman has returned. Can the Boxcar Children find out what's going on before the ghost tours are ruined?

When the Alden children accompany their grandfather on a trip to Seattle, they discover clues throughout the city, seemingly planted just for them.

The Reddimus Society needs the Aldens' help returning lost artifacts. But as the children travel across continents, a rival is hot on their heels.

The Aldens are preparing for a yard sale when they find an old wooden mask in the trash behind a neighbor's house and discover it is an old Native American mask from the Hopi tribe. When the mask is stolen from their garage, the Aldens vow to find it before the weekend Pow-Wow. But with such little evidence, will they be able to find the mask in time? Illustrations.

Henry, Jessie, Violet, and Benny have never been to a drive-in movie theater before, but they_re visiting a friend who owns one. The children love to eat popcorn in the car and watch movies under the stars. But strange pranks are disrupting the fun_one night the sound system starts playing loud music during the movie, and a couple of the theater employees seem to be hiding a secret. Then, late at night, a ghost is seen walking around the empty grounds...

"Hidden behind the wall of their guest room, a mysterious journal leads the Aldens on a search for a valuable collection"--

"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.

Jessie and Henry have their robot stolen before the big tournament.