They're Here. More are Coming. Don't Worry. We have a Plan.
Dr. Molly Caffrey, a high-level government crisis management consultant from the Blackwood Institute whose job is to create contingency plans for use in emergencies ranging from natural disasters to nuclear war. In order to have "all bases covered", one of her plans, code-named Threshold, is developed for dealing with the unlikely eventuality of first contact with aliens. After the crew of a U.S. naval vessel reports an encounter with a UFO, and many members of the crew subsequently die, the Threshold protocol is activated.
Caffrey's Threshold plan calls for the formation of a secret government task force known as the Red Team.
Threshold learns that the aliens are attempting to rewrite the DNA of the human race using, in part, an audio signal that somehow alters some people's body chemistry in such a way that they become alien themselves.