Nolan and Karns play federal agents investigating a number of truck hijackings along state highways. The plaintiff, Naish, who asks for assistance in the first place, is actually the man behind the gang staging the robberies and goes to the police as a decoy. The G-men go under cover
and, posing as truck drivers, hijack one of the gang's trucks, impress the crooks, and work their way into the gang. An extremely well-paced job. The title refers to women on the highways who flag down the trucks to be victimized.