Jan Martin, sister of government chemist Paul Martin, realizes she is being followed by enemy agents after her brother. She ignores him at the Panama airport and embraces a stranger, Mike Lawrence, instead. Enemy agents Lake and Wilton are convinced that Mike is her brother and attempt to trap the pair. They get away but Jan disappears. Disguised with a black wig and new makeup, Jan becomes Dolores and gets a job singing at a cafe. Spotting Jan without her disguise, Mike follows her down an alley where they are trapped by Raynor, another espionage agent. They get away and Jan also gets away from Mike. Later, both Mike and Jan are captured and the agents realize that Mike is not the brother they are after. Paul is brought to the hideout, but Mike gets the drop on them.