After six months in Regiment purgatory, SAS loner Jamie 'Geordie' Carter has been assigned to a new squadron. Tasked with flushing out the troop's bad apples, he's never been more exposed. And when someone tries to silence him, Carter is unexpectedly pulled from the team and given an even deadlier assignment.

Viktor Koltrov is a charismatic Ukrainian general, and the second-most popular man in the country after the president. His stunning victories against the Russian military machine have made him the public face of a resurgent Ukraine - and a top target for the Kremlin's assassins.

Now Carter must protect Koltrov as he embarks on a sensitive operation to flush out high-ranking traitors in the Ukrainian government. Eliminating the fifth columnists is vital if Kyiv is to defeat the invaders.

But keeping the general alive in a war zone won't be easy, even for a hardened Regiment man. And as Koltrov hunts down his prey, Carter begins to realise that the infiltration of the establishment runs far deeper than he had ever imagined.

If Carter's going to win, he'll need all of his wits and survival skills to stay ahead of the danger. Because the biggest threat isn't from Moscow. It's from the enemy within . . .