MI5 are protecting a renowned Serbian war criminal Niko Grecic, before he's transported to The Hague. They believe that Richard Dempsey, an MI6 traitor, will be looking for Grecic and Harry wants Dempsey killed.
However Adam has a history with Dempsey: they were close friends until he turned traitor and sold Adam out during an operation in Serbia.
Adam confronts Dempsey who claims he has been a double agent all along. But Dempsey's MI6 boss has died and no one else seems to know anything about his mission.
He decides to believe Dempsey is now on his own mission - to prove Dempsey's innocence even if it means disobeying orders.
Harry's finally persuaded by Adam that Dempsey's the wrong man. Dempsey walks free and Grecic safely testifies at The Hague.
But six months later, Grecic receives a surprise visit from Dempsey, who assassinates him.