The daughter of a British Government engineer who is working on a defence protect is kidnapped, and the only way she will be safely returned is if he agrees to betray secrets to enemy agents.

Bodie's mental state is called ino question when he becomes obsessed with a local Hell's Angel motorcycle gang, gradually sending him further and further behind in training. Is he cracking up?

A CIA agent is murdered in London, prompting CI5 into launching a fake arms deal with the terrorists who were responsible for the killing. But the gang uncover the plot in time, taking Bodie hostage and using him as their meal ticket to escape the country.

In the midst of a shoot-out during a drugs smuggling investigation, Doyle meets and falls for Ann Holly, only to discover that CI5 suspect her of being closely linked to the scam herself.

Cowley finds himself under suspicion when a former colleague of his is arrested for being a double agent. So just how deeply involved is the CI5 Chief?

A team of Hong Kong police join CI5 in London to help crack a local heroin supply and protection racket. It's down to Bodie and Doyle to expose a scheme to smuggle drugs to the US by teams of Triads and European agents.

CI5 move in to protect the daughter of a South American President after his son - and her brother - is assassinated on the field of a polo match.

A hitman is employed by a group of East German officials to assassinate a reporter who is planning to publish a report in which their new fighter plane is branded as a potential death-trap.

A drug addict is murdered by a pusher who then hastily discards the gun, only for it to be found by a young boy-who then accidently shoots his friend in the process. The pusher then goes in search of the boy in an attempt to retrieve the gun and at the same time has to try to avoid his own people who are in pursuit of him.

Silver bullion is being shipped into Britain via the Iron Curtain, only for it to be hijacked by one of the group's own officials.

Bodie and Doyle are undergoing intense training in preparation for an assignment where they are protecting a foreign official...at the same time, two potential killers are receiving similiar training to prepare them for the assassination of the same official.

Bodie, Doyle and their latest girlfriends are on a quiet weekend in the country when they unwittingly get caught up at a farmhouse siege in which they must try and escape from a group of gun-toting fugitives.

Bodie and Keller, an old acquaintance from his days in the SAS, go undercover in order to trap a would-be assassin by posing as hitmen offering to do the job themselves - in order to fake the killing. But Keller turns out to have an ulterior motive.

Various industrial secrets and highly-valuable arts treasures are being stolen and sold on by a gang who are using the blind routine of Customs to their full advantage. CI5 devise a trap to stop the thieves in their tracks.

CI5 discover that a possible terrorist attack is being planned, and the only clue they have in solving it is a German girl who is found collapsed in a church and suffering from amnesia.

Annie Irving, an extreme left-wing preacher - and former flame of Cowley's - becomes the target of a hitman when one of her meetings comes to London. Cowley assigns Bodie and Doyle to protect her, unaware that the would-be hitman is right under his nose.

A leader of a criminal gang offers to surrender himself if in exchange he is guaranteed protection for his family.

CI5 are assigned to protect a visiting American Ambassador from a renowned hitman called Ramos, who is hot on his trail. But after only one apparent assasination attempt at his life, Ramos appears to give up - only for him to turn up again at CI5 HQ itself.

A suspect being held under CI5's supervision is found dead in his cell - apparently after a fatal blow administered by Doyle. A public inquiry ensues and an influential lawyer calls for CI5 to be shut down. It's left to Cowley in fighting to save the organisation he founded.

CI5 manage to undercover a series of financial blunders between a group of builders and council officials after a site of newly-built houses on a council estate are found to be crumbling.

A dummy run that has been staged for the visit of a Middle Eastern official is found to have been recorded by a foreign student, subsequently leading CI5 to suspect a security leak.

An attempt to start up a street war is launched by a gangland breakaway opposition group, but their leader appears to have an ulterior motive in his actions.

Bodie and Doyle are shocked to discover that Cowley appears to be selling nerve gas to a group of East Germans in order to line his own pockets, and are assigned by his rival Plumb to track their boss's every move.

Bodie is offered the opportunity to clear up all his gambling debts by a foreign diplomat - who in exchange wants to have some vital secrets from CI5.

Charles Nesbitt, an expert on chemical weapons, threatens to contaminate the water sources of London with a lethal hallucogenic drug and in order to back up his claims, plans several small 'demonstrations' in warning to the local authorities - including CI5.