When an MI6 agent is found to be keeping records of his missions to protect himself from betrayal he unwittingly makes himself a priority target. But how do you silence the most dangerous man imaginable? Send him into hell on earth. While Alex King is sent into Northern Iraq to tidy the loose ends of a botched mission, the archipelago of Indonesia is under communist threat from within its own military. A consortium of worried businessmen call for desperate measures and seek the services of an assassin.

At a US research facility funded by the military and clandestine agencies, a super-virus has been created as a first-strike military weapon. During its conception, the anti-virus has furthered the possibilities of medical research by decades. Such is its potential, treachery has struck from within. If the virus is released, then the anti-virus will be worth billions to the pharmaceutical industry. Isobel Bartlett worked on the project and knows its potential.

Court Gentry is known as The Gray Man—a legend in the covert realm, moving silently from job to job, accomplishing the impossible, and then fading away. And he always hits his target. But there are forces more lethal than Gentry in the world. And in their eyes, Gentry has just outlived his usefulness. Now, he is going to prove that for him, there's no gray area between killing for a living-and killing to stay alive.

David Rivers is an elite-level assassin. He’s an expert in the art of violence. Honing his skill first as a Ranger, then as a mercenary, and now as a CIA contractor conducting covert action around the world. But in his secluded mountain home in Virginia, David Rivers lives a double life. There, Rivers is known as a caring husband to his new wife and the doting father to his young daughter. Soft targets to his enemies. Half a world away, on a mission to assassinate a foreign operative, Rivers uncovers his worst fear.

Alex Reeve - known as OPERATIVE 66 - is a former special-ops soldier and one of the UK's most lethal weapons. Previously a member of SC9, an elite covert unit with a remit to assassinate the country's enemies, Reeve was framed for treason and now lives a nomadic existence - as the merciless killers he once trained alongside hunt him down. For a chance of a normal life, Reeve must expose and dismantle the sinister SC9. So when a series of brutal killings in Germany have all the hallmarks of an SC9 tactic.