A man is savagely murdered outside Portland, and Detective Mason Callahan finds blood-spatter evidence that tells a troubling story. Files reveal the murder victim, Reuben Braswell, was a radical conspiracist. In his home, investigators find pages of diatribes against law enforcement as well as ties to Mason’s fiancée, FBI special agent Ava McLane. The victim was her informant - and had strong reasons to be paranoid. 

All Detective Mason Callahan wanted was a quiet fishing trip with the guys - a chance to get away and unwind before Halloween. Until he finds the body of his boss, Denny Schefte, near their remote Oregon cabin. Now all he wants is to catch the sadist who slit Denny’s throat and covered his face with a mask. Mason was the last person to see him alive and will stop at nothing to find his friend’s murderer.

Twenty years ago in the dead of night, four seemingly random individuals pulled the ultimate heist and almost walked away with half a million dollars. But by daybreak, their plan had been shot to hell. One of them was in the hospital. One was in jail. One was dead. And one got away with it. Arden Maxwell, the daughter of the man who disappeared all those years ago - presumably with the money, after murdering his accomplice - has never reconciled with her father's abandonment of her and her sister. 

FBI Special Agent Ava McLane solves crimes; she doesn’t witness them. When she’s trapped in a mall without her weapon as a shooter picks off victims, she hides with a wounded teen and prays for her survival. But that’s only the beginning.... An epidemic of mass shootings has has swept across Oregon. The young shooters terrify the public, committing random murders before taking their own lives. 

After a congressman’s tortured body is found dangling from a Portland bridge, the FBI joins the Oregon State Police to investigate the case - and FBI Special Agent Ava McLane, still recovering from a bullet wound, hunts the twisted killer alongside the man who captured her heart, police detective Mason Callahan. But once a third body appears and all evidence points to a serial killer, the public furiously clamors for answers - and the couple’s relationship grows fractured under the pressure.