Special Branch - Season 4 (1974)

The Special Branch team face an explosive situation when they are asked to find the thieves who stole a top-secret weapon fitted with a new laser device. The weapon is unstable - and could blow up at any time.

When two children run riot in the luggage department at London Airport and cause a mix-up with passengers' baggage, it inadvertently results in the discovery of a sinister secret - which leads Craven to investigate two army officers.

Craven is put in charge of security for a vital debriefing exercise being held at a derelict mental institution. He has difficulty deciding which which of the group is mad - the interrogator, the KGB agent, or the woman being interrogated.

It's blackmail with a difference. Key public figures are having dirty linen washed in public by a pirate radio station. Craven and Haggerty tune into the people behind the scheme and DS Ross becomes a DJ.

Craven's personal problems intrude into his police activities. Opening his door to a midnight caller, he finds his ex-wife, Claudia. Within hours Craven finds himself suspected of being connected with his wife's terrorist activities.

A spy is killed in Canada and Craven must find out what connection he had with a young au-pair working in London. A girl he apparently never met, but whose welfare the dead man had watched from afar.

The Special Branch team face a quandary. Why should Morales, a foreign VIP whose help is vital to Britain, turn out to be as dubious as the thugs who relieve him of a fortune in diamonds? Craven is given the job of finding out.

Gunter Hellman, a student revolutionary, is allowed into Britain with his wife Gisela to continue his studies. The condition of his entry permit states that he must not engage in political activities. Suspecting that he has, Craven and Haggerty pay him a call.

Why has Strand suddenly begun a relationship with a lady colleague and started to drink heavily? Has the pressure finally caught up with him? Or is he playing a solo game to unmask a villain.

The media carries the news: Murder at Maison Igor's.' Craven and his team must use their own approach to get a line in an unseen gunman now stalking the London streets intent on further killings.