A routine subway ride turns out to be anything but when Candy (Jean Peters) is mugged by a man named Skip McCoy (Richard Widmark), who's in search of valuable microfilm that Candy is carrying. Aware of the film's important nature but not its exact contents (government secrets intended for Communist spies), Candy must now enlist the help of her ex-boyfriend Joey (Richard Kiley) to find the thief and get the microfilm back.