Henry Faversham, a diplomat in a South American country, is boarding a plane to come home to England when police chief Garcia tries to arrest him for stealing a huge sum of government money. When Faversham threatens to blow up the plane Garcia has to let him go but in London Faversham, expecting Garcia to follow him, hires McGill to bug a room in which the two men will meet and in which he will prove his innocence. Unfortunately Garcia abducts Faversham and McGill races to save him.
Bigoted plantation owner Marcus Spencer bullies and abuses his African work force,refusing to pay them an agreed sum. Their ally is Father Ignatius Loyola,a Jesuit priest and Spencer gets McGill to investigate him. In fact he is an ex-mercenary called Porter,believed to be dead but,after locating and speaking to Porter's father,McGill sees that he is genuinely repentant and anxious to help the oppressed Africans. For this reason,it only seems right to defy the vile Spencer and his wife and go over to the side of the angels.
Private eye Nolan is shadowing the unfaithful husband of Mrs. Arnoldson,who is planning to flee the country with the much younger Angela. However there is something about his employer that Nolan recognizes from the past and he calls in his old friend McGill after the Arnoldson chauffeur shoots at him. Later the man does kill Nolan and McGill is framed for the murder. With the police on his trail he must work out why they killed Nolan.
McGill is hired to go to Greece in pursuit of Dalby, an oceanographer who has stolen plans relating to the commercial viability of sea farming. He catches up with his man but finds that Rudnik,an Albanian agent,is also interested in the stolen papers. In fact Dalby's flight is a cover for his real mission - to locate and destroy a secret Russian submarine base. McGill joins him and C.I.A .agent Packard in the assignment but they have dangerous opponents who take McGill's colleagues prisoner.
British agent Ruth Klinger apparently defects to the East Germans,who set her a loyalty test involving her old flame McGill,in Germany to track down the missing Johann Liedkind. Johann is in fact part of a neo-Nazi revivalist group,the discovery of which places McGill in a dangerous situation. But at the same time he is faced with a dilemma. How can he escape and save Ruth with him without blowing her cover?
Marcelle is a blind French girl, whose adoptive mother is robbed and killed. She places an advertisement for help in locating the killers which is answered by McGill. Strangely, however, both Marcelle's uncle and the French police try to warn McGill off the case. It soon becomes apparent that the innocent soirees that Marcelle regularly holds for other blind people are being exploited by a drug smuggling gang, placing her in danger.
Whilst Garfield Cameron,who owns a mining company in the African country of Kalunga,supports local politician Masuto,who seeks the country's independence, Garfield's son-in-law James Baldwin fears that Masuto's coming to power will mean the end of the mine so he and henchman Turner commit acts of sabotage on the mine to scapegoat and discredit Masuto. Garfield calls in McGill to investigate and expose the saboteur but,with the mine closed,he finds the country in a state of revolution.
In Italy McGill is employed by the wealthy Count Ugo to find his younger brother Silvio,who is shortly to come of age and thus will inherit a large sum of money,providing that he signs a document to accept it. Silvio is living in London with an artists' commune and makes it quite clear to McGill that he does not want his brother's money. However Count Udo has sent one of his heavies after McGill to make sure that Silvio signs on the dotted line.
Dr. Norbert is a lawyer on an advisory committee concerned with the international legislation of space travel and he is set up by an opponent of the committee who photographs him in a compromising situation with a prostitute. He goes to McGill for help but McGill finds that the doctor's opponents - and likely blackmailers - are not just rival businessmen but government representatives as well. So is there another reason for the blackmail?
Five years previously a gang of armed robbers pulled off a gold bullion heist but only one of the, Keith Earle,was caught and sent to prison. Now that he is out he is on the trail of the hidden loot as well as catching up with the former gang members who left him to his fate and to whom he is only too ready to dispense rough justice. McGill is engaged by the police to locate both the murderous Earle and the stolen gold.
Jane Farson cannot understand why her ailing father is refusing to see her, a supposed instruction which her brothers make sure is carried out. Then Jane sees 'Property of a Gentleman',part of her father's extensive art collection,up for sale, She is perplexed as he has always refused to part with any of his paintings. She calls in McGill,who finds her brothers uncooperative but a night time visit to her father's room proves to be very educational - providing the answer to Mr. Farson's uncharacteristically odd behaviour.
Living in exile in Sweden with his daughter Chantal,Dr. Maza has written his memoirs,in which he claims that the president of his country was murdered by the usurper Colonel Haider. Maza asks McGill to escort Chantal to London with his manuscript but,on the way, Chantal and the papers are taken by Haider. Fortunately Dr. Maza's publisher is on hand to help McGill rescue Chantal and her father and get the papers to London.
Joan Heinemann,an old flame of McGill,fears that she is being stalked by a mysterious woman though her husband Jason,who is having an affair,tells her that she is imagining things. When her dog is killed and thrown into the river she is sure she is right and calls in McGill,who uncovers a secret from Joan's past involving a traumatising occurrence within her family.
Eleanor Duzac hires McGill to follow her much younger husband Bernard,whom she believes to have a mistress. The trail leads to a Paris club La Guillotine,well-known for staging mock executions,where Mcgill sees Bernard with his lover Janine. Acting on Eleanor's instructions Mcgill goes to Janine's flat to pay her off but finds that she has been killed and he has been set up as the murderer.
Sir Dennis Galt, a senior British Civil servant, has been playing away whilst his wife is on holiday in Bermuda. When he learns that she is due home he breaks up with Magda, his mistress, but she runs off with a diamond brooch belonging to Galt's wife that he has lent her. To avoid scandal Galt asks McGill, not the police, to retrieve it before his wife returns and an irritating jeweller tells her what has happened. Magda claims to be from an aristocratic Austrian family who live in a castle but nevertheless her boyfriend Johnny is a ne'er-do-well who wants to sell ...
McGill has assembled a gang of burglars,supposedly to steal an art collection from a fairly inaccessible fortress in the Pyrenees mountains. Whilst they are in an old farm-house testing the glider which will gain them access to their destination,they are interrupted by Anne Weekes,a tourist who has stumbled off the beaten track,and McGill has to dissuade some of the gang members from killing her. He also has to act fast before they realise that they are not actually going to steal art treasures but top secret microfilm,on behalf of the British government.