Security wants a retired brigadier of the British army to be stopped from accepting a job offer from a sultan, deadly force is requested.

Callan in brainwashed into believing that Hunter is the leak in the Section and that he has also killed Lonely and framed Callan for murder. In his drugged state Callan kills Hunter and is shot down by Meres.

A freelance German mercenary organisation who specialise in eliminating foreign security sections have their sights set on the Section.

The Section's new Hunter has Callan pulled from the field.

Callan must prove that a young biochemist is not giving information to the East.

After Hunter's death Meres and Calln must fetch the new Hunter from East Germany.

Hunter's secretary, Liz, is out for someone's blood.

Callan and Cross must break a Russian spy out of prison, where he has voluntarily surrendered himself to, and kill him.

Callan helps a former agent out of a blackmailing business.

Hunter, head of the Section, requires the services of his best operative, David Callan. Callan had been 'retired' from the service due to his growing conscience, disrespect for orders, and concerns about the people he was ordered to eliminate. Callan now working as a bookkeeper, a job he despises, is offered to be reinstated into the Section if he kills Schneider, an international arms dealer.

Hunter wants Callan to stop a blackmailing Lord from selling the negatives used in the blackmail to all and sundry.

Callan is assigned to disrupt a romance between a government worker and a suspected spy. Reluctantly he delves into his bag of dirty tricks.

The new Hunter cannot decide if Callan is to return to the Section or not.

An exchange of captured agents with the Soviets goes sour.

Callan and Cross are assigned to protect a woman whom Callan becomes involved with.

When Cross kills an innocent bystander it's up to Callan to cover for him, but even he cannot decide if it was an accident or murder.

Callan brings confusion into a Russian spy network.

Callan must use the wife of a rocket scientist as bait to lure the same scientist to Britain.

The French O.A.S. carry an internal war into England. Callan and Meres must sort out the mess.

A parlamental candidate recieves a death threat.

Under threat of being placed in a red file, Callan is coerced into helping the Section hand over an ex-SS officer, Strauss, to the Israelis.

Callan must stop an old friend, Clarke, from going back to Africa, where he was training mercenaries, else Hunter will have Clarke killed.

Two CIA agents request the help of Hunter's Section in killing a Chinese agent, who has been trading in nuclear secrets. But his real mission in England is to kill Hunter.

Callan is lured into going to Berlin, where Hunter wants to use him as a sacrificial lamb to facilitate the planting of a British mole.

When somebody beats Lonely up, and Callan finds out who it was he turns the table on Hunter.