The officers of the Special Branch mount a dawn raid on the homes of the members of a suspected spy ring.
Cowley suicides shortly after an unproductive round of questioning by Eden in gaol, which leads to an embarrassing public coroner's inquest. Jordon investigates a scientist being vetted for a sensitive position and all agree he's too far left for further consideration, yet he still succeeds.
A small boat arrives at a beach in Kent where illegal aliens are unloaded, but the police bag the smugglers and all bar one of the Pakistanis, now quite ill, who seeks refuge with an immigrant rights activist.
The son of a trusted officer of the special branch has become radicalised while away at university, trying to join a gang of riot-minded militant socialist students. This threatens to break up his family, and his father's position.
A girl lands at Heathrow from Rhodesia, but owing to Britian's break of diplomatic relations, she has no valid passport. A young officer is supposed to mind her until she can be sent back, but takes her for a tour instead.
A girl being held for giving official secret documents to the Russians faces a long gaol term, but an exchange offer for a Briton arrested in Moscow is offered. The officers suspect she's far more than she seems to be.
Jordan's methods cause friction in an overseas British Embassy when he goes to investigate the theft of ten thousand pounds.
Jordan goes undercover as a prisoner to uncover a convicted spy's secrets.
An ex-colonial policeman is pressured to return to Africa to testify at the trial of a onetime Mau-Mau warlord, but he adamantly refuses.
Jordan and Inman go in search of a missing Russian ballerina.
Craven find himself under suspicion of accepting a bribe.
Haggerty's appointment to Special Branch immediately brings him into conflict with Craven - he believes that Craven is on the trail of a man who is already dead.
Craven finds the tables turned when he is accused of hounding a self-confessed fraud.
Haggerty and Craven target a team of vicious muggers.
The Special Branch team are assigned to protect the captain of a Polish passenger and cargo ship who believes he is going to be killed.
Special Branch joins forces with a bomb-disposal expert to stop a terrorist bombing campaign in the heart of London.
The body of a young girl is found floating in the Thames - is it murder, suicide or something worse?
A deranged man has taken a hostage and threatens to blow up a block of flats. Craven must act quickly to avert disaster.
British-born Hollywood star Sue Arden arrives in London to rehearse a play, accompanied by a tip-off from the F.B.I that she could be a target of a murder attempt. Craven, Haggerty and North are assigned to protect the actress, but the job and the murder threats are not all they appear to beâ€¦
Craven finds himself investigating a man accused of being a traitor, but has his doubts as to the truthfulness of the accusations.
Craven is puzzled as to why he has been asked to carry out twenty-four hour surveillance on a couple who are engaged to be married.
Craven and Haggerty are under the gun to find a kidnapped diplomat's daughter before she is killed.
The team is assigned to protect a visiting foreign diplomat.
Craven and Haggerty are assigned to investigate if a photographer is a threat to national security.
The team are on the trail of Rehfuss - a deadly assassin who has managed to get into the country.
Craven and Haggerty are hot on the trail of a traitor has broken out from prison.
An experimental weapon is stolen from a military research facility, but the thieves are unaware the weapon is unstable.
Tensions run high as Craven and Haggerty investigate two army officers.
Craven provides security for the debriefing of a captured KGB agent.
Craven and Haggerty investigate the broadcasting of compromising information about public figures on a pirate radio station.
Craven is appalled to find himself implicated in his ex-wife's terrorist activities.
Craven must unravel the connection between a recently-killed spy and an au pair.
Craven has to investigate a morally dubious but strategically important foreign VIP who has been robbed of a fortune in diamonds.
A German student revolutionary has been allowed into Britain under the strict condition that he does nothing political. Craven and Haggerty are made to ensure that he sticks to the terms of his deal.
Is Strand's erratic behaviour a result of the pressure he is under or is he playing a much more dangerous game?