Peter Karczag, an American immigration officer, travels to Cuba in search of an illegal immigration ring. He disguises himself as Josef Gombush, a Hungarian looking for a way into the states, and asks for help from Palinov, a seedy café owner who runs the ring. Peter meets Marianne Lorress, a beautiful Jewish woman who is trying to get to South Carolina where her father lives. Peter falls in love with Marianne, and after some initial reservations, she falls for him also.

But Palinov sends his goons to check Peter out, and they find out he’s a cop. Palinov has unseemly designs on Marianne, so he exposes Peter. She turns her back on him and goes with Palinov. With some other refugees, they board a small plane. Peter returns to the states and, with the help of his chief, Frank Westlake and a navy pilot, they track down Palinov’s plane. Knowing they will be arrested if they land at any airport, and without enough fuel to get back to Cuba, Palinov’s pilot crash lands in the Everglades. The pilot has a three-man raft and gets in with Palinov, who forces Marianne to get in also. When the other refugees try to board, one is shot dead. Peter and Westlake board an air boat and pursue. Westlake goes after the refugees who are stumbling through the swamp. Peter takes the boat and pursues Palinov. The raft springs a leak and the two men and Marianne are forced to proceed afoot. The pilot is bitten by a water moccasin. Palinov and Marianne arrive at the boat to find Peter waiting for them. Palinov draws his gun and forces Peter out of the boat but not before Peter drains the gas. Marianne chooses to stay with Peter, even though she knows she will be arrested. Palinov takes off into the fog. Peter promises to do what he can for Marianne.

Good atmosphere, sort of a Casablanca feel, without any pretense to seriousness. The plot is pretty exciting. The acting is fair. Hedy Lamarr doesn’t act so much as she just walks around looking like Hedy Lamarr — which works for me.