Kris and Rob Lawter are excited to be traveling the world on a small luxury ship, their dream vacation. Retired from a high-stress career in government, Kris and her husband, a recently retired airline pilot, hope their good marriage will catch fire without alarm clocks in the way. But when Rob sees their neighbor tossed overboard in the dead of night, they have no choice but to get involved. Then their friend gets beaten up in Cádiz, and only the Lawters see the deadly connection. Unless Kris finds the key to a cipher she found in the dead man's cabin, the Lawters might be next.