Targetting a Chicago-based espionage ring, Inspector Erskine (Efrem Zimbalist Jr.) goes undercover, posing as an injured spy named Eric Cross. It is Erskine's goal to identity the ringleader of the spies, a person known only as "Constantine." In an ironic twist, the spy boss is revealed to be fatally ill and is written off as expendable--and as a result, Erskine must keep "Constantine" alive long enough to die in bed. ~ Hal Erickson, All Movie Guide