Claire is only seven when her college-age sister, Alison, disappeared on the last night of their family vacation at a resort on the Caribbean island of Saint X. Several days later Alison's body is found in a remote spot on a nearby cay, and two local men employees at the resort are arrested. The evidence is slim, the timeline against it, and the men are released. Years later Claire is living and working in New York City when she meets Clive Richardson, one of the men suspected of murdering her sister. On an obsessive pursuit of the truth, Claire shadows Clive, waiting for the slip that will reveal the truth.