Tommy and Val are adventurers who love to dive. They board the sailing ship Erehwon, ready for a trip filled with excitement and maybe a little danger on the high seas. Of course, there's more to their trip than sightseeing. They are in love, but Val questions how real Tommy's feelings are. Is his love for a season or for life? She hopes the trip will decide where they stand. The Erehwon sets sail under the cover of an ominous fog, and Val prepares to spend time alone with Tommy without the distraction of friends, family and academics. When a fellow shipmate goes missing, though, Tommy and Val's romantic urges are put on hold. The passengers and crew search for the lost traveler but find not a trace. The captain presses on, despite the macabre mood that has settled like a cloud over his ship. Soon, another passenger vanishes, but that's not the worst of it. Something on the Erehwon is hungry for blood. Tommy and Val's love conundrum is the least of their worries as they find themselves trapped on a ship that wants them dead-a ship that might never make it back to port.