While on assignment in East Germany Callan is captured and sent to Russia by the KGB where he is ruthlessly interrogated.
In the meantime, the Department have put it around that Callan has died and they stage a funeral and arrange a burial with a coffin and a real body in it. The only people who know that Callan is still alive are Bishop and Hunter.
Lonely refuses to believe that Callan has died and starts making a nuisance of himself, but this is soon handled by the ruthless agent Cross. Cross and Stafford are told by Bishop to go and collect the KGB agent Richmond. It is Bishop who really values Callan and arranges for an exchange between Richmond and Callan. Hunter tells Callan that he did not want to lose Richmond, in effect telling Callan that he considers him expendible.
(Pictured at right is Russell Hunter as Lonely).
Hunter No. Four is leaving the Department, and he and Bishop decide that Callan would be a good replacement. Very much against his will, Callan takes up his position as the new Hunter only to find that a red file exists with Lonely's name on it. There is also a hit out on Callan himself.
Callan hasn't seen Lonely since his time as a prisoner of the KGB. He tracks Lonely down and tries to arrange for him to leave the country with false papers, but the plan goes wrong. Fairly soon it becomes apparent that whoever is trying to kill Callan is using Lonely as bait.
(Pictured at right is Edward Woodward as David Callan).
Callan, as the new Hunter, tells Bishop that he wants a Mobile Communications Facility, which is his way of describing Lonely behind the wheel of a taxi cab in communication with Headquarters. By this means Callan also manages to put Lonely onto the payroll of the Department.
A man called Kitzlinger contacts Bishop and Callan and tells them that he wants one hundred thousand pounds in return for a list of all the SIS Agents working behind the iron curtain. Callan agrees, as one of the agents' names has been released already, and this man, Bristac, was shot and wounded as he left East Germany.
Toby Meres is back from Washington. He poses as a KGB agent offering a similar amount to Kitzlinger on behalf of the Russians to establish whether Kitzlinger is genuine or not. In the end he and Callan discover that a woman named Myra Kessler is behind the whole scheme, but things are a bit more complicated than this.
(Pictured at right are Edward Woodward as Callan and Anthony Valentine as Meres)
Bishop tells Callan that a British official working in Moscow has been expelled as a spy, despite the fact that he isn't one. In return, Bishop says that they must expell a Russian embassy employee and they must harass one of them until he wants to go back.
The job of harassment is handed to Cross. The man is named Medov and he is the cultural attachee to Moscow with a wife and young daughter. In the end Medov cracks under the strain, and approaches Cross asking for asylum. He says that once you start being harassed you become suspect. While all this is happening, Medov's young daughter attacks Cross who accidentally strikes her over the head with his gun butt.
The girl ends up in a critical condition in hospital with brain damage.
(Pictured at right is Patrick Mower as Cross).
SIS Agent Cross injures a fourteen year old Russian girl by accidentally hitting her on the head. She has sustained brain damage and lies paralysed in hospital.
Dr. Snell is certain that Cross is cracking up, and feels that Cross shouldn't go on any more jobs for the present. Callan, who controls the section, disagrees and sends Cross on a mission to guard a Soviet poet while Meres is employed following the Russian KGB assassin Borov. During the mission Borov attempts to kill the poet, and Cross is shot and killed.
When he hears that Cross has been killed, Callan breaks all the rules by going out on the job himself. He locates Borov and shoots him. Borov's last words are: 'He let me kill him'.
Callan is suspended from the job of Hunter by Bishop, and Dr. Snell tells him that Cross was really seeking a way out, and had committed suicide.
(Pictured at right is Edward Woodward as Callan with Russell Hunter as Lonely).
Professor Peter Rose is an idealist, dreaming of a world where all scientists share their secrets regardless of Government. He proposes to sell British secrets to Russia via a man whom he met in Amsterdam. Professor Rose thinks that he is a harmless book-seller, but in fact he is a cold-blooded KGB executioner called Colonel Tamarish.
Callan and Lonely break into Professor Rose's cottage to photograph some of his documents, and everything goes well until Lonely pilfers a shiny silver ornament. Professor Rose notices it is missing and calls in the police. Embarrassingly for Callan, he and Lonely are arrested and Hunter must pull a few strings to have them released.
Colonel Tamaresh arrives in the UK and very quickly realises that the Police are following him. He lures two inexperienced young Officers into Epping Forest and murders both of them, before joining Professor Rose at his cottage.
Callan is sent to kill Tamaresh with as little fuss as possible. He carries out his job leaving a very shaken Professor Rose who will spend the rest of his life looking over his shoulder.
Richmond is still on the loose. SIS have information that the KGB are interested in one of their agents, a woman called Flo who is presently serving 14 years in Wormwood Scrubs.
Callan removes Flo to a safe house, but she escapes and finds Richmond. Callan and Toby Meres track her down, but when they arrive they find that events have taken a tragic turn.
Callan has retired from the Department, runs his own military memorabilia shop called 'The Old Brigade' and is living with a woman called Margaret. Lonely has also moved on. He has a successful plumbing business and is engaged to be married.
But you are never retired when you work for The Department, and when Callan hears from the new Hunter that his services are required he discovers that a man named Hagggerty is writing a tell-all book which names Callan as a professional killer. Hunter tells Callan that it is a non-Departmental matter, and that it is between Callan and Haggarty. Callan enlists Lonely's aid, gets his magnum pistol out of storage at the bank and prepares to kill once again.