St. Kilda and Emma are tracking a yacht named Blackbird. Emma knows the boat's intended cargo is lethal. What she needs to find out is whether it's biological, chemical, or fissionable. And she's only got seven days to uncover the truth . . . or a major American city will be lost. Fortunately, she's working with a new partner as menacing and distrustful as the worst enemy she's ever faced—Mackenzie Durand.

But Emma and Mac aren't the only eyes watching Blackbird. Taras Demidov, an expert in extortion and execution in the pay of oligarchs running the Former Soviet Union, is also waiting in the shadows, determined to intercept a fearsomely powerful arms dealer with the money, weaponry, and connections to alter the geopolitical balance.