The chairman of the KGB is hunting a spy who also happens to be a high-ranking Kremlin official who has been leaking secrets to the British. Bucharensky (codename Kyril) is ordered to defect to Britain in order to panic the traitor into making a mistake. Making his way across Europe to London, Kyril attracts the attention of the intelligence services of both East and West and becomes a target for both sides. Waiting in London is Kyril's deadliest enemy, Royston – a KGB mole whose life now depends upon silencing Kyril before he can disclose Royston's identity as a Soviet double agent.

This compelling Cold War spy mini-series was scripted by John Hopkins from a book by John Trenhaile.