Alexander Strange lives and works aboard a fishing trawler in Naples, Florida writing about news of the weird. His laid-back lifestyle is disrupted when a feisty author of conspiracy books insists he investigate the death of her brother in Key West. Her name is Silver, and the cops think her brother's death was an accident, a scuba diving mishap caused by nitrogen narcosis. But Silver doesn't buy it. She believes he was murdered, and the motivation behind his killing is far more noxious. When she tells Alexander her brother’s last words to her were, “I found a mermaid,” it’s a story too good for a weird-news reporter to resist. But when the bullets start flying and the sharks start circling, he realizes he’s gotten into something literally over his head.