Heather Lawrence was on her way to a much needed vacation in Salzburg when, mere hours into the flight, the Houston FBI agent wakes up to see passengers showing horrific symptoms of an unknown infection. As the virus quickly spreads and dozens of passengers get sick, Heather fears she's witnessing an epidemic similar to ones her estranged husband studies for a living, but his airborne contagion might have been deliberately released.
While Heather is quarantined with other survivors, she works with her FBI colleagues to identify the person behind the attack. The prime suspect is Dr. Chad Lawrence, an expert in his field, and Heather's husband. Their marriage has been on the rocks ever since he moved out after announcing that his career took precedence over his wife and future family.
As more victims are claimed just days after the initial outbreak, time's running out to track down the killer, one who might be even closer to the victims than anyone ever expected.