A deadly vineyard holiday: a Martha's Vineyard mystery

When the President of the United States vacations on Martha's Vineyard, his daughter, sixteen-year-old Cricket Callahan, yearns for a Roman holiday of sorts, far from the Secret Service agents who regulate her every move.
While fishing alone on South Beach early one August morning, sometime investigator and full-time food and fishing enthusiast J. W. Jackson sees a teenage girl strolling along the shore. They chat, and he lets her land a bluefish, but as soon as she spots some approaching headlights, she asks directions to Edgartown and trots away down the beach.
She's out of sight by the time a Jeep full of armed and anxious Secret Service agents pulls up. The young woman is Cricket Callahan, the Secret Service has lost her, and the President and First Lady must be informed that their child is missing. J. W. heads for home and a good breakfast with wife, Zee, his encounter with Cricket already taking on anecdotal possibilities. One thing's for sure: He's glad he's not the agent who has to tell the President the bad news.
J. W.'s amused detachment is short-lived, however, when, arriving at his cottage, he discovers Cricket hiding under the tarp in his truck. She had ducked behind a sand dune until the Secret Service disappeared, then hid in J. W.'s old land Cruiser. What do you do when the U.S. Secret Service is searching the neighborhood for a possibly kidnapped young woman who is now standing in your kitchen? If you are J.W. and Zee, you teach her how to cook blueberry pancakes before calling the police to report her whereabouts.
J.W. fully expects Cricket to return to the presidential compound after a few hours in his cozy kitchen, so he's surprised when Cricket asks and receives permission to stay on for a few days. Could there be a reason the President wants Cricket living incognito with J.W. and Zee? Could she be in danger if her actual whereabouts are known? And could the danger possibly come from within the Secret Service itself?
Working with a wide network of contacts both on and off the island, J.W. pursues elusive conspirators from the Gay Head Cliffs to the clam flats of Edgartown until, at last, he and the enemy meet face-to-face.