After someone is killed in the subterranean project called "Shadowzone," a NASA captain is called in to investigate. In the project, sleeping subjects are induced into a deep EDS state whereby they become portals to a parallel universe. Unfortunately this causes adverse reactions in the subject, and something gets through the portal, the consequence of which is an attrition problem.

Together, a weary cop and an all business FBI agent, team up to catch the latest homicidal manic: The Rain Killer. Just when they think that all the clues have been washed away, they find the one last clue; the one that's been in plain sight.