Shannon is the most daring of "Merlin's Maidens." But her hellfire temper has recently landed her in trouble with her superiors, and she fears her days at the Academy might be numbered. However, she's offered a second chance. Her assignment: stop the ruthless French assassin who is targeting the family of a top British ballistics expert.

She jumps at the opportunity, only to discover that her commander-in-chief has made a deal with the Devil. The mission is to be a joint venture with Russian Intelligence-and a sinfully sexy spy she has clashed with once before. Alexandr Orlov got the best of her on that occasion, but this time she's determined it won't happen again.

Orlov is no more happy about the assignment than she is. He's all too aware that lovely, lethal British agent is impervious to his notorious charm with women. Indeed, sparks fly whenever they rub together, and Orlov fears that the job will be perilous enough without the threat of personal fireworks. But orders are orders. Masquerading as a tutor and governess, he and Shannon are dispatched to a remote Scottish castle, where they must learn to work together in order to protect an elderly dowager and her two precocious grandchildren from harm.

The arrival of houseguests from London adds further complications. Are Lady Sylvia and her friends innocent of ulterior motives? Or does their visit have a more sinister design? Caught up in a dangerous duel between duty and desire, Shannon and Orlov have to decide who is friend and who is foe. Trust is a double-edged sword. A ruthless enemy is watching. and planning to turn their growing passion into the most deadly weapon of all.