Master Sergeant Casey Schultz is the deadliest weapon in the US Army. A sniper and reconnaissance specialist, Casey is a field-promoted veteran of Desert Storm and Afghanistan, now deployed to the brutal frontlines of Ukraine. Trained by the best, she is a solitary, unforgiving killing machine, a unit of one who feels more at home behind enemy lines than in friendly territory. She trusts her personal knives and handgun more than any military-issued weapon, embracing her role in a man's army with lethal efficiency. But her skill has drawn an admirer. A mysterious stranger begins to appear in the shadows, always moments before or after Casey eliminates a target. At first, she fears the constant pressure has finally broken her mind. To admit it would mean a one-way trip back home, so she keeps the terrifying encounters secret. The truth, however, is far darker than a delusion. Her fan is not a man, but Satan himself-and Casey is strangely attracted to him. She knows this infernal company is wrong, yet she finds herself thoroughly enjoying the Devil's presence. As her mission blurs with an impossible, hellish attraction, Casey must choose: her duty to her country, or the seductive darkness of her new companion.