A fast-paced thriller from the author of the international bestselling Shepherd series.

The gruesome killing of more than 300 white squatters in a South African village is still unsolved when the alleged assassin enters a storage facility in the US and takes several hostages.

No demands and an obvious play for time leave hostage negotiators on edge. When the FBI is called in, they bring Dr. August Burke, a young man with James Dean looks and a brilliant mind capable of seeing behavioral patterns where others can't. Unfortunately, Burke hates being around people. Can he put his social anxieties aside and solve the mystery before it's too late?

Together with FBI Special Agent Carter, Burke finds the door to a secret laboratory beneath the storage facility. Is this what the culprits are really after? Soon Burke realizes they are dealing with an enemy who is willing to kill thousands without batting an eye.

Across the globe, Constable Isabel Price picks up her gun and starts the hunt for the killer behind the village massacre, even if that means losing everything. She has no intention on bringing him back alive. Her thirst for revenge leads her to the US, and her path intertwines with the hostage takers.

Between Isabel Price's quest for bloody vengeance and August Burke's uneasy gift, Spectrum weaves a web of intrigue and complex characters into an action-packed crime novel.