An international jewel thief known only as the Catbird breaks into a lavish Denver mansion during a reception for a British earl. His daring robbery is interrupted by Rosalind Hayes, who becomes the only living person able to recognize him. Rosalind, however, is more interested in finding her missing brother than worrying over possible danger from the Catbird.

It is only after Rosalind's life is threatened that she reluctantly joins forces with Adam Moreaux, a Pinkerton operative who has been chasing the Catbird for years. Together they discover that both her brother and the Catbird have unwittingly become linked by the disappearance of the Petrovna parue, a famous setting of Russian jewels. Torn by fear for her brother, a growing attraction for Moreaux, and a fascination with the notorious thief, Rosalind's pursuit leads her and Moreaux to a dangerous confrontation on the heights of the Rocky Mountains.