Whilst Doyle is on a date with Kathie Mason his flat is robbed and a powerful laser gun which he was given to test is stolen. After an attempt to kill him, he and Bodie make inquiries as to who would have stolen the gun and Maurice, one of their informants, is shot dead with it. Another colleague is taken prisoner as bait to flush Doyle out in the open by the thief, Preston, a disgraced ex-cop sent to prison on Doyle's evidence and now after revenge. But who knew Doyle's routine that well that he - or she - was able to tell Preston about the gun?
After informant 'Nosey' Parker has tipped them off about the drug-dealing habits of boxer-turned-gangster John Coogan, CI5 interrogate Coogan's younger brother, Paul,who dies, seemingly after Doyle has hit him. Coogan gets his powerful lawyer to instigate a committee to determine whether or not CI5 should be disbanded but Cowley's own investigations throw light on the true cause of Paul's death as well as exposing Coogan's violent activities and confirming the need for the department's continued existence.
Israeli minister Asher Biebermann is kidnapped from outside the Festival Hall by two men known as Frank and John, whilst under police protection. He is taken to a house in a residential area where he chained to the bed. Acting on a tip-off, CI5 discover a photograph and a cassette tape in a telephone box and, using such information as they offer, locate the house, planning to break in from next door and rescue Biebermann.
When a bomb goes off in a restaurant where he is eating, causing some fatalities, Bodie assumes that he was the intended victim. In fact the real target is a seemingly inoffensive accountant who actually has been given a new identity after giving evidence against a gang of American mobsters. The chase is on as to who will reach him first - the villains, the F.B.I or Bodie, with a puzzled Doyle in tow.
Chief Constable Green operates a zero tolerance policing system bordering on fascist dictatorship. When a gay youth counselling centre is attacked by masked men one of the staff suspects the police are behind it and goes to see Cowley. Bodie and Doyle themselves become victimized after being charged with a minor traffic offence. However Green and corrupt inspector Chives are about to find out that they have picked on the wrong people - especially as Doyle has photographic evidence of police corruption.
Barry Martin was a founder-member of CI5 with Cowley and trains Bodie and Doyle in unarmed combat, but he has turned 'rogue' for money, delivering a witness who was to be kept under wraps for an upcoming drugs trial to his killers. He shoots another man dead and wounds Cowley, who ends up in hospital. Having tumbled to his plan, the lads pursue Martin to an underground car park where he eludes them, leading to a final shoot-out.
Temple-Blake building firm stands trial for corruption following dishonest warding of contracts by local councillor Webb. Its nervous accountant is murdered to stop him confessing all and jury members bullied into returning a not guilty verdict. Cowley is not happy and when Bodie and Doyle meet an under-cover fraud officer who posed as a workman to expose the company's use of sub-standard materials and got beaten up, CI5 determine to bring down all concerned.
Years earlier spy Thomas Darby sold out and defected to the Russians. Now he has returned to England. Cowley is anxious to locate him and find out from him the names of other double agents. Men with guns are also after Darby - to silence him before he can pass on any information.
Bodie and Doyle are assigned a routine bodyguard operation for a 'Mr. X', Middle Eastern diplomat Hanish, but no sooner have they picked him up than they are pursued by gunmen who seem to know every move on his itinerary, rendering two safe houses anything but safe and forcing a final showdown on a houseboat.
Bodie is delighted to re-encounter old flame Marikka Schuman, an East German film star, with whom he spends an idyllic time in his flat. However he is unaware that Marikka's husband and henchman Willis have set him up to take the rap for an assassination, causing him to go on the run from his CI5 colleagues. Although he is eventually cleared there is no happy ending for him with Marikka.