It is set to be the greatest bounty hunt in history...

Fifteen names.

There are fifteen targets, the finest warriors in the world - commandos, spies, terrorists. And they all must be dead by twelve noon today. The price on their heads: almost $20 million each.

One hero.

Among the names on the list, one stands out. An enigmatic marine named Shane Schofield, call sign SCARECROW.

No limits.

The Increment - the elite assassination unit of the SAS.

Three years ago Matt Brown was thrown out of the unit for questioning an order - and he was on the way out of the SAS. Now, just when he thinks he has put military life behind him, he finds himself dragged back into action.

MI6 are demanding he helps a giant drugs company destroy copies of its medicines being produced by Eastern European gangsters. But the mission is not what it seems.

When the National Security Agency's invincible code breaking machine encounters a mysterious code it cannot break, the agency calls in its head cryptographer, Susan Fletcher, a brilliant, beautiful mathematician. What she uncovers sends shockwaves through the corridors of power. The NSA is being held hostage - not by guns or bombs, but by a code so complex that if released would cripple U.S. intelligence.