The Citadel — Robert Doherty

At the awful dawn of a nuclear age--at the painful birth of the Cold War--the Citadel was constructed in secret beneath the Antarctic ice. Housing the most devastating weapon imaginable, it was a safeguard against an unseen threat far more potent than the growing Communist menace. Now, six decades later, America's destruction seems all but assured--because the enemy has re-emerged from the shadows of time.

And the Citadel has been breached.

The commander of Section 8--a covert force of misfits assigned the impossible missions no one else will touch--Captain Jim Vaughn must now lead his unit into the unknown to diffuse a nightmare of astronomical proportions. The future hangs in the balance--and the ultimate survival of humankind is in the hands of men with nothing left to lose . . .