Playing for Keeps — Joan Lowery Nixon

For fans of Gillian Flynn, Caroline Cooney, and R.L. Stine comes Playing for Keeps from four-time Edgar Allen Poe Young Adult Mystery Award winner Joan Lowery Nixon.
 
        Rose Ann can't believe her good luck. Her grandmother, Glory, needs a last-minute roommate for her bridge-tournament cruise to the Caribbean. But Glory doesn't really need a companion. She's eager for Rosie to meet her friend's grandson, Neil, a brainy guy full of facts about baseball, among other things. Once Rosie is aboard the ship, though, someone else catches her eye -- a boy her own age, who introduces himself as Ricky Diago. But after the ship sails, something doesn't seem quite right. Rosie sees only Ricky's uncle, Mr. Diago. Even stranger, Neil swears that Mr. Diago is actually a famous Cuban baseball player from the Cincinatti Reds.
        Then, after a day excursion in Paradise Beach, Rosie is approached by another boy who claims he's Ricky Diago. She's certain he's not the person she met at the beginning of the trip. Suddenly Rosie finds herself caught in a high-stakes game of international intrigue with life-or-death consequences. Who is the real Ricky Diago? And how far will Rosie go to help him?
        With her trademark expertise, Joan Lowery Nixon interweaves politics, baseball, and romance in a masterful novel of suspense on the high seas.
 
“[An] engaging mystery.” �"Kirkus Reviews
 
“[A] fast-paced combination of suspense and romance.” �"Booklist
 
“Satisfactory teen mystery.” �"VOYA