Ambitious personal trainer Cassidy Novak has gained national fame for starring on Sink or Swim, nicknamed SOS, a hit game show set aboard a Tall Ship. She hopes the prize money will help to launch her dream of owning a chain of fitness centers. Not only does she lose the competition and have to walk the plank in the finale, but after the game show ends, the terror begins. Upon returning to her small Massachusetts hometown, Cassidy discovers she has attracted a stalker masterminding his own twisted game. She struggles to focus on her health club job and celebrity endorsement opportunities, but her stalker has other plans.

As her former competitors get knocked off one-by-one, Cassidy refuses to play by his bizarre rules. She's also being shadowed by hunky photographer Zach Gallagher, who has been assigned to capture her personal moments for a spread in the local newspaper. She wants to trust Zach, but fears he may not be the nice guy that he seems. With or without Zach's help, when the stalker forces a showdown by threatening her family, Cassidy must once again walk the plank - this time for her life.