When people start dying of unexplainable symptoms in Los Angeles, the government turns to Biodefense, a top-secret agency against bioterrorism. For the five members of the team, what they thought could never happen has come to pass: a nanotechnological weapon of mass destruction has been set loose. And one thing becomes all too clear to Biodefense's Alan Thorpe: the virus was developed and spread here--by a sleeper cell within our own borders--and no one knows how to stop it.