Jennerson, the captain of a freight ship, loses his vessel when it hits what appears to be an old mine. The event is viewed as a tragic accident, which cost the life of one of Jennerson's crew. But the FBI, led by Erskine and Rhodes, is following up indications the incident was deliberately staged. Indeed, the mine, stolen from elsewhere, was newer than a World War II mine. Jennerson and an accomplice are after $40,000 in insurance money. What Jennerson doesn't know is that his wife is having an affair with the accomplice. At the same time, the sunken ship's cargo included chlorine, which create a deadly gas should its containers rupture -- and a tidal wave is approaching, which will rip the sunken ship apart.