My name is Molly Caffrey and I work for the Federal Government. I deal in worst-case scenarios, the unthinkable. On September 16th, 2005, the unthinkable happened. An extraterrestrial object appeared off the bow of a naval freighter. The entire crew was exposed to a high frequency signal. Some died instantly. Others began to change. They are now stronger, more resilient. They dream of alien landscapes. And they are driven by the impulse to infect others. Several of the crewmen are now loose in the United States. They will strike anytime, anyplace, anyone. Their goal: to turn us into them. But I have a plan to stop them. That plan is called "Threshold".