Although Penelope Hamilton Wynch doesn’t especially miss her estranged husband, she does yearn for the excitement of the old days, when they worked together on assignments from the Pinkerton Agency. So it is no surprise that, despite their irreconcilable differences, she finds herself agreeing to help him on a case once again. He needs her to infiltrate the household of H.A. Comstock, a wealthy industrial magnate who has been the victim of factory sabotage and an assassination attempt.
As Pen works the case while dodging her husband’s attempts at reconciliation, she encounters another old flame who is looking more and more like the prime suspect. Pen must resist her renewed feelings for the man, as she races against time to stop the saboteur and would-be assassin before he tries again.