The Aldens are spending a week at Camp Seagull on beautiful Claw Island. But as soon as camp begins, they realize that someone is not playing fair. Everything begins to go wrong for the Aldens—they lose their luggage, Henry misplaces the camp flag, and the campers on the other team use one of Jessie's ideas to score points for themselves. Are some campers so desperate to win the Olympics that they are willing to cheat? The Boxcar Children

...

The Alden children visit a family friend at his apple orchard which is rumored to be haunted, but instead of a ghost they find that some of the families' valuable antiques are being stolen.

The Alden children meet Mike Wood and a strange chain of events begins. Mike's house is mysteriously burned down, a man in a blue hat appears, and the Alden's uranium mine is in danger of being sabotaged. The four children solve the mystery.

People line up around the block to buy Mama Tova's cupcakes. But who could be trying to steal her secret recipe? The Boxcar Children follow clues to a cupcake contest, where they must use their mystery-solving skills to find a thief.

"The Aldens spend the summer on their aunt's ranch! The ranch is a beautiful place, but it's also the source of trouble between Aunt Jane and Grandfather. As the Boxcar Children explore the land, they make an amazing discovery. Will it help mend Aunt Jane and Grandfather's relationship?"--Publisher's description.

While vacationing at a friend's country home, the four Alden siblings try to find a long-missing, priceless brooch and investigate the existence of a ghostly stream.

The Aldens investigate when the arrival of several suspicious characters in Greenfield coincides with a mystery involving a popular boy actor.

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.