Readers with a high tolerance for coincidence and implausible plot twists will best appreciate this stand-alone thriller from bestseller Patterson (Double Cross) and collaborator Roughan (You've Been Warned). Katherine Dunne, a 45-year-old New York City heart surgeon, has more than her fair allowance of emotional baggage-her philandering husband, Stuart, died four years earlier in a scuba diving accident; she had a fling with Stuart's younger brother, Jake; and her three children suffer from varying degrees of dysfunction. In an attempt to repair her family, Katherine plans a relaxing cruise on a yacht captained by Jake. Her new husband, Peter Carlyle, a top Manhattan criminal attorney, claims he has to stay behind because of an important trial, but once Katherine and family set sail, it soon becomes clear Carlyle has his own agenda. The cruise turns into a struggle for survival, including a predictable shark encounter and a less predictable, if no less silly, giant snake attack. If the lead characters were more than walking cliches, their struggles and changing relationships would leave some impression. Still, the action is all that really matters, and Patterson delivers what his audience wants in spades.