Season 1

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.

A teenager's vow of vengeance leads to Inspector Jordan interrupting a wedding and Superintendent Eden accepting a parcel that contains death. Before the day is over both men have cause for concern.

Informed that the manuscript of a Russian author's novel which has been smuggled into Britain is a forgery and could discredit the Goverment, Inspector Jordan goes against orders and investigates the claim.

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.

Is there something sinister going on behind the facade of 'The Children of Delight' - a group of hippies who have arrived on Eden's patch. Detective Sergeants Webb and Gifford go undercover to investigate.

Superintendent Eden is on the spot. The Security Commission has met to consider the leak that tipped a spy during the Troika affair. The detective is cleared - but told that he cannot continue his role as Special Branch controller.

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.

When a member of a foreign embassy is caught shoplifting in London, but tries to hide her status by willingly accepting arrest, Superintendent Inman takes an interest in her employers.

Jordan's methods cause friction in an overseas British Embassy when he goes to investigate the theft of ten thousand pounds.

When a KGB officer is sent to London to coordinate security measures with the SB team for the forthcoming visit a Russian VIP, Inman instructs Jordan to help him - with disastrous results.

Sent to investigate the death of the son of a pro-British oil sheikh in a bomb plot, Superintendent Inman finds a hotbed of intrigue and dangerous international situation about to explode in his face.