"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"--Back cover.
"When pieces of equipment start disappearing from the new Aquamarina playground, it's up to Violet the mermaid and her best friend Wally the narwhal to solve the mystery"--OCLC.
