Doctor Sophia Perry has always been a fighter—the youngest virologist and hematologist in the nation, she's made a career of outsmarting diseases. But her own battle is one she can't win. With cancer stealing her future, Sophia is determined to make her remaining time count. When a deadly outbreak sweeps through a Syrian refugee camp, she throws herself into the investigation, keeping her diagnosis a secret from everyone, including the soldier assigned to protect her. Communications Sergeant Connor Button has his own scars from war, both seen and unseen. Back on active duty after a devastating explosion, he doesn't expect his next mission to awaken something inside him he thought was lost: hope. Sophia's brilliance and determination spark a fire in him he hasn't felt in years, and he'll do whatever it takes to keep her safe—even when her relentless pursuit of answers puts them both in danger. As violence threatens the camp and deadly truths come to light, Sophia and Connor must face more than just their enemies. With time running out, they must decide if love is worth the risk when every moment could be their last. In a fight against an invisible enemy, can they hold on to the one thing neither of them expected to find: each other?