The Undersea Mystery Club is going on a treasure hunt! In Book 2 of the series, Violet and Wally discover an old chest hidden in a sea cavern. In order to uncover who put it there and why, they'll have to figure out how to open its rusty lock!

The mystery of the hidden chest sends Violet and Wally on a deep dive into the history of Aquamarina. Along the way, they learn about the importance of staying connected to the past and the value of real treasures-like cherished memories with friends. After the adventure, readers can flip the to the back of the book to learn more about the job of a historian and follow instructions to create a time capsule of their own!