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.

CI5 become aware that an assassination plot on a group of visiting Greek Royals is being planned using a rifle that has a range of over two miles. But they must find out who is the gunman and what is his target - before it is too late.

On leave from CI5 with a hand injury, Bodie takes a day trip with his girlfriend and finds himself face-to-face with the leader of a terrorist group. He captures him but then the rest of the gang arrive and trap Bodie and his girlfriend in a nearby vicarage, leaving him unable to alert his colleagues back at CI5 HQ. With barely any clues as to his whereabouts, Doyle and Cowley go on a chase through the countryside to try and locate Bodie.

A CI5 agent is murdered, leading to the discovery of a man who is dying as a result of plutonium poisoning. This links CI5 to a further plot involving the imminent explosion of an A-bomb at the same bowling alley. It's left to Bodie and Doyle to try and de-activate the fuse before it takes them and the whole of London with it.

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.