Niki Garat tolerates her job and the city, but she lives for her summer vacation with her grandfather at his sheep camp in the stunning Big Horn Mountains of Wyoming—until this year.

When the U.S. comes under attack, including an aggressive attempt by foreign invaders to locate nuclear missiles hidden throughout remote western lands, the serenity of her mountain refuge is shattered. As area ranches are commandeered, neighbors and friends, including Deuce, her childhood infatuation, band together.

Throughout their struggle to stay alive, Niki begins to understand what came between her and Deuce, but before past mistakes can be corrected they must endure a terrifying manhunt and a desperate fight for survival.