Treasure Trouble — Carolyn Keene

In Treasure Trouble, Nancy, George, and Bess are headed to Barnacle Beach for a pirate-themed birthday party. But when the treasure chest filled with party favors disappears, playtime is over. With the help of a mysterious treasure map, the Clue Crew needs to reclaim the missing loot before the party's completely ruined. In Double Take, the Clue Crew has competition -- one of their classmates has started a rival sleuthing club! Can Nancy and the girls solve the latest case before the phony detectives do?