The secret of the mansion: Trixie's summer is going to be sooo boring with her two older brothers away at camp. But then a millionaire's daughter moves into the next-door mansion, an old miser hides a fortune in his decrepit house, and a runaway kid starts hiding out in Sleepyside!"
The red trailer mystery: Trixie and Honey’s friend Jim has run away from Sleepyside–before anyone could tell him that he is the only heir to the huge Frayne fortune. The girls set out across upstate New York in a trailer to track him down . . . and stumble onto another mystery along the way!
The gatehouse mystery: When Trixie and Honey explore an abandoned gatehouse, they discover more than dust and spiderwebs. Stuck in the dirt floor is a huge diamond! Could a ring of jewel thieves be hiding out in Sleepyside?
The mysterious visitor: Not long after her family becomes wealthy, Diana Lynch's long-lost uncle appears and starts ruining her social life, causing Trixie Belden to investigate whether Uncle Monty is an imposter out to steal the Lynch fortune.
The mystery off Glen Road: When a storm blows through Sleepyside, the Bob-Whites’ clubhouse is crushed by a fallen tree. Trixie, Honey, and their brothers set to work at the Wheelers’ game preserve to raise the money to repair it. Of course, no one expected Trixie to stumble across the trail of a dangerous poacher!