Iraq veteran Cal Winter, cashiered from the British army for assault, has a secret. It leads to his blackmail, and employment as an assassin for an organisation known as The Firm. Only five years more service doing deniable wet-work will see him walk away free. Cal is assigned to protect Russian oligarch Sergei Belov, a billionaire dissident who made his name whistle-blowing on the cover-up of a nuclear accident...