While vacationing at her uncle's sheep ranch, Trixie and the Bob-Whites track down the thieves who are behind the mysterious disappearance of several sheep.

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.

Thirteen-year-old Trixie Belden and her friend Honey make several trips to the local marsh in search of herbs and flowers to replace their teacher's plant specimen collection and to look for the pirate treasure that is rumored to be hidden there.

While organizing an ice carnival to raise funds for her pen pal's school library, Trixie investigates a mysterious problem facing Regan and a run of thefts and accidents in the neighborhood. There's a new kid in town-a tough boy from New York City who wears a black leather jacket and pointy cowboy boots. Trixie doesn't trust him for a second. She's sure about one thing: Don Mangan is trouble!