What if the president of the United States authorized a secret biological weapon attack against an American city as part of a homeland security experiment intended to provide the government with real-time information showing how people would react after an actual terrorist's attack?

And what if you and your family happened to be vacationing in the target city when that government experiment occurred?

That's the situation that ex-Navy SEAL Trace Austin and his family find themselves in when they go on vacation to Fort Lauderdale, Florida, and become trapped behind barbed wire, subject to quarantine and martial law.