Sidney Allen is a Fed. Part of the Australian Federal Police's K block, a unit doing whatever it takes in order to stop terrorist attacks on home soil.
But when young Muslim men on the Terror Watchlist start turning up dead, Sid and his partner, Haifa, have to work out what's going on.
Sectarian war? Drugs? Retribution? For Sid, there's nothing unclear about a bullet to the head and a severed hand. Someone is sending a message.
Deciphering that message reveals a much wider threat and Sid and the agency have to decide just how far they'll go to prevent a deadly attack.
Time is running out ... for them and Australia.