Marshals Bill Henry and Brett Stone have their man Yazzie Chavez cornered only to have the outlaw escape during gun play with Chavez and his henchmen. Learning later that Chavez has run north, the two lawmen head through Dodge where Henry rescues a young woman and her son from the hands of a ruthless Dodge City Sheriff.
The three head toward Denver unknowing that Chavez is aboard the same train. Henry learns from JR Morris, the DC Chief, that a hired asassin, a man called Chameleon, is trailing Henry. Reaching Denver Chavez makes his way to his aunt's hideaway joining with others in a planned train heist of a million dollars in gold. Henry is close once more in confronting Chavez only to have him slip away hours before tightening the noose.
The Chameleon, in various desguise, pursues Henry in Denver forming his plan on when and where he will kill the Marshal. Their paths criss cross with Henry oblivious to the Chameleon's desguises until a simple clue of pouring a shot of whisky puts Henry fast on Chameleon's heels and the man's abduction of the woman and her son.