A Communist plot to destroy the Panama canal sees a number of passengers join forces in an attempt to overthrow the crew of a ship carrying an atom bomb en route, while an eminent doctor aboard the ship is blackmailed into activating the missile or risk the murder of his daughter.
The dialogue is a bit juvenile, and MacLane seems to be hamming it up as the crooked captain, nicknamed "Scarface" for obvious reasons, who smokes a durry like the Penguin and will do anything to honour mother Russia. Erickson is the opportunist who stumbles upon the plot while attempting to escape South America for a relatively minor (by comparison) feud with a local kingpin. Grey is simply wasted, with little to do except wallow in her cabin aboard the doomed ship of "Captain Scarface".
The villains are simply described as 'Communists', political jingoism and highly appropriate for 1953, but the film is little more than a B-grade quickie, peddling an array of hokey plot contrivances for a 69 minute back-slapping exercise devoted to subduing a red threat. Hastily resolved, there's very little action of which to speak and despite attempts at intrigue, it's pretty dull an uninspired.