The new British Ambassador to the Republic of Ireland, Harriet Smith, arrives in Dublin to discover that the Irish government is accusing the British of sinking one of their trawlers in the Irish Sea. Together with MI6 agent John Stone, Smith uncovers the truth.

Ambassador Smith gives the battered British wife of a Saudi diplomat refuge in the embassy when he beats her up and attempts to kidnap their son, even though this jeopardises a lucrative aircraft contract with Saudi Arabia.

When a young British girl is jailed for drug smuggling, it seems a positive start to an Anglo-Irish initiative. Then Smith discovers that the girl works at the same bar as her 19 year old son Nate. Stone investigates whether he is connected to any illegal activity.

The ambassador's assistant is held hostage by a man brandishing a canister of nuclear waste, in protest at the number of children he says are dying from nuclear waste pollution of the Irish Sea by British nuclear facilities.

A young rent boy found dead in a Dublin hotel bedroom, after having sex with visiting British minister David McNaughton, leads a British government minister to order a cover-up, which is carried out by Stone too thoroughly.

MI6 fear that Smith has been targeted for assassination, but she refuses to compromise her official engagements. A former MI6 officer, Sir Robert Beauchamp, is intent on publishing his memoirs before he dies of cancer, facing Smith with more tough decisions.