A man walks into a trendy Los Angeles restaurant — a disgruntled ex-employee with an automatic weapon — and seconds later, thirteen people are dead and thirty-two more have been wounded. It is a heinous act of mass slaughter that haunts Homicide Detective Peter Decker.

But, though eyewitnesses saw only the lone gunman — who apparently took his own life after his bloody work was done — evidence suggests more than one

At 8:15 in the morning, a small commuter plane carrying forty-seven passengers crashes into an apartment building in Granada Hills, California. Shock waves ripple through Los Angeles, as L.A.P.D. Lieutenant Peter Decker works overtime to calm rampant fears of a 9/11-type terror attack. But a grisly mystery lives inside the plane's charred and twisted wreckage: the unidentified bodies of four extra travelers. And there is no sign of an airline employee