Kill or Be Killed follows the misfortunes of Robert Warren (Lawrence Tierney) who falls victim to a classic "wrong place, wrong time" scenario. Angry with a customer who owes him money, Warren confronts his debtor heatedly. Minutes later the customer is murdered by two men, one of them the film's true villain, Victor Sloma (George Coulouris). When a witness places him at the scene of the crime, Warren flees from the police and narrowly escapes by hopping on a ship bound for the South American jungle. On board, he meets and falls in love with Maria (Marissa O'Brien), the wife of Gregory Marek (Rudolph Anders). In a tragic twist of fate, Gregory turns out to be Sloma's partner, and soon Warren will be hunted again by both men. In a frantic final sequence on a jungle plantation, Robert Warren fights for his life, his innocence and the woman he now loves.