It's the end of summer, and Devlin Quick is invited to join her best friend Booker's family on vacation at their summer home in Martha's Vineyard. Booker has a science project for school- to take a daily bucket of water from the Vineyard Sound and submit a sample to an oceanographic DNA lab. From that, they can actually tell you what species of fish have been in those waters- striped bass, blues...and sharks! But Devlin comes up with something else in her bucket from the days when pirates hid treasures along New England coastline. With access to the crime DNA lab back in NYC (courtesy of her mother), Dev is going to solve the mystery of this treasure...and figure out all of the secrets Martha's Vineyard is hiding.