While in Italy investigating a THRUSH plan to divert the Gulf Stream with heavy water, Solo finds himself eluding THRUSH guards, and ends up hiding under the bed of Pia Monteri. Solo escapes a shotgun wedding, the family feels Pia's honor has been compromised, and the girl's American uncles retired Prohibition-era gangsters ""Fingers"" Stilletto, Enzo ""Pretty"" Stilletto, and Federico ""Feet"" Stilletto are called. At the island headquarters of Louis Strago, Illya is tortured by Strago's sadistic female assistant, Miss Diketon. Solo joins forces with the Stilletto brothers to try and rescue him.

In spoof of ""My Fair Lady,"" Solo is recuperating from a fall into a Venice canal, Illya teams with Mark Slate to uncover Baroness Bibi de Chasseur, a THRUSH money courier who has contact with the treasurer of THRUSH. They recruit a barroom entertainer, Rosy Shlagenheimer, an exact double, to impersonate her. The switch is made, but in the confusion the Baroness makes another switch and poses as Rosy, then finds herself falling in love with Slate.

While in Italy investigating a THRUSH plan to divert the Gulf Stream with heavy water, Solo finds himself eluding THRUSH guards, and ends up hiding under the bed of Pia Monteri. Solo escapes a shotgun wedding, the family feels Pia's honor has been compromised, and the girl's American uncles retired Prohibition-era gangsters ""Fingers"" Stilletto, Enzo ""Pretty"" Stilletto, and Federico ""Feet"" Stilletto are called. At the island headquarters of Louis Strago, Illya is tortured by Strago's sadistic female assistant, Miss Diketon. Solo joins forces with the Stilletto brothers to try and rescue him.

Solo investigates a girl's school for the daughters of VIP's, including Miki Matsu, who has valuable secret information from her father, a Japanese diplomat. THRUSH agent Jason Sutro has gained the cooperation of the headmistress, Hester Partridge. The assistant dean, Verity Burgoyne, and all of the girl students have been brainwashed by Sutro to go into a trance upon hearing a recording of Brahm's Lullaby, and are ordered to kill Solo.

Solo and Illya protect Miranda Bryant, the wife of a presidential candidate, from a THRUSH plot to kidnap her, not realizing that she has already been kidnapped and replaced with a double Irina, an unwitting dupe of THRUSH. When they do catch on, the candidate, Senator Bryant and his aide Fairbanks, agree to play along but Fairbanks is the one behind the plot to put a THRUSH agent in the White House.

An off-broadway actress is murdered during a phone call to U.N.C.L.E., and Solo and Illya investigate a connection between the show and a sudden malfunction in U.N.C.L.E.'s communications. The understudy, Janet Jarrod, takes over the lead role, and Illya joins the cast to find the jamming device.

Jacqueline Midcult writes a best selling novel, The Pieces of Fate, which U.N.C.L.E. recognizes as being based on a series of missing THRUSH diaries. She loses her memory during a THRUSH attempt to kill her, and THRUSH agents Ellipsis Zark and Jody Moore, a book critic, plot to kidnap her and find out where she found the diaries. Solo and Illya take Jacqueline to a small town where her Uncle Charly and Aunt Jessie live, to try and revive her memory, but Zark and Moore follow and they all converge on the attic where the diaries are hidden at the same time.

Dr. Rutter, after inventing antimatter, hides out in Suburbia under the name Willoughby because he fears his creation will be used destructively. Solo and Illya take a house there to find him. But THRUSH agent Miss Witherspoon also wants to find Rutter, and when Rutter sends his neighbor Betsy after some rare medicine from the pharmacist, Fletcher, the chase is literally on the find Rutter first.

Solo and Illya are assigned to protect Dr. Fazie Nahdi, a Gandhi like peace advocate, during a conference. Nellie Canford, a high school teacher, becomes linked to their efforts when her dental work begins receiving radio transmissions. Mahdi stays at the home of Brutus Thor, who is actually a THRUSH leader who is trying to kill him and Illya is trapped in a room full of toys that begin firing real bullets.

Solo is nearly killed by a superhuman, robotlike girl, Margo Hayward, one of an army of such devices invented by Dr. Pertwee for THRUSH. Illya joins up with Margo's ex-roommate, Andy Francis, and finds the laboratory, where a roomful of robots attack them.

Scientist Adrian Cool spots a UFO approaching earth on his radar. His daughter, Coco is kidnapped, and Illya follows and he's captured also. Simon Sparrow, a power-mad millionaire, has faked the approaching UFO to secure power for himself as the representative on earth of the ""aliens"". Sparrow captures Solo and puts him in an experimental wind tunnel to kill him, but he is saved by Corinne. Coco develops a crush on Illya; while they are trying to stop Sparrow, they end up aboard his ""UFO"".

Solo goes to Sweden to obtain a new suspended animation device from Dr. A.C. Nilson, but the device and its inventor are taken by THRUSH. The doctor's daughter Neila helps Solo find him, and the doctor's assistant, Inga Anderson also feigns cooperation but is actually working for THRUSH agent Heinrich Beckmann. Beckmann uses the device to invade U.N.C.L.E.'s Scandinavian headquarters, and only Solo has a chance to stop him.

THRUSH agent Abbot Simon takes over the monastery at St. Thomas to use the mountain location to aim a new laser gun at a long distance target the Louvre in Paris. Solo visits the area and meets Andrea Fouchet, and together they try to stop Simon before he destroys the world's greatest art treasures.

A dissatisfied THRUSH collaborator tips U.N.C.L.E. off to a new deadly hiccup gas. A pendant he wears leads Illya to Greenwich Village and an art gallery run by Mark Ole, a THRUSH agent. Starving artist Sylvia Harrison joins Illya, who is nearly suffocated at the hands of a foam producing machine.

Brothers Simon and Peter Sweet both rival THRUSH leaders vying for promotion, do not realize that the toy hula doll they possess has an extremely powerful new U.N.C.L.E. explosive inside that is activated by heat. As the outside temperature rises, Illya and Solo try to recover it with the help of Wendy Thyme. Solo poses as a representative of THRUSH Central, but Mama Sweet a real member of THRUSH Central appears on the scene.

In Rome, American tourist Darlene Sims becomes the unwitting carrier of a perfume atomizer with a secret formula. THRUSH uses a suave ladies man Cesare Guardia to charm Darlene, but he falls in love with her in the process.

Solo and Illya visit the laboratory of Dr. True, who has discovered how to extract gold from seawater. But Dr. True dies from a poison given him by THRUSH agent Randolph, and Randolph also kills his wife Amanda. The gold extraction formula was distributed in portions by True to his daughters, in inscriptions on a photo of himself. Solo and Illya meet Sandy True, who accompanies them to Rome, to find her half sister Margo, now unhappily married to the destitute Baron de Fanzini to London, to find the next sister Imogen, who has been arrested by a Constablefor indecent exposure and finally the Alps, to find Yvonne, who is breaking off an unhappy relationship with Karl Von Kesser. But after decoding the message in Japan, Solo, Illya and Sandy are captured by Randolph and taken to THRUSH central for execution.

Frank Cariago, the U.S. head of a crime syndicate, is under pressure from Uncle Giuliano. Cariago decides to buy a movie production directed by Sheldon Veblan so his girlfriend, Ginger Laveer can have the starring role. But the picture is a disguised plan to drop a bomb on the family's biggest rival-Las Vegas.

Investigating the shipment of a tidal-wave machine by THRUSH, Illya ends up aboard a merchant vessel run by Captain Morton. Morton is obsessed with his past disgrace in a court martial, and the crew is on the verge of a mutiny, which Illya leads just as THRUSH arrives to take possession of the device.

Solo and Illya go to Algiers to obtain a rare old book containing a THRUSH code from Pierrot La Mouche who has stolen it from his boss, Colonel Hamid. But La Mouche has a high price he wants U.N.C.L.E. to help him obtain Janine whom he is in love with.

Solo and Illya are responsible for the security during Waverly's upcoming address to his alma mater, but the campus is seething with protest. Illya joins the demonstrators, and meets Minerva Swight, the daughter of the dean. The head of the board of regents, Jonathan Trumble, is a THRUSH agent, and he hires campus agitator Gregory Haymish to try and kill Solo and Illya, while Trumbull's THRUSH superior, Number 24, undergoes plastic surgery so he can impersonate the dean during the ceremony and kill Waverly himself.

A THRUSH code is hidden in a dress pattern, and Solo and Illya go to the garment district and encounter the design shop of two down on their luck designers and their model Ramona and the cutter who has a crush on her, Jerry. THRUSH also tries to retrieve the garment, but Ramona keeps forgetting where she left it.

Solo and Illya visit the laboratory of Dr. True, who has discovered how to extract gold from seawater. But Dr. True dies from a poison given him by THRUSH agent Randolph, and Randolph also kills his wife Amanda. The gold extraction formula was distributed in portions by True to his daughters, in inscriptions on a photo of himself. Solo and Illya meet Sandy True, who accompanies them to Rome, to find her half sister Margo, now unhappily married to the destitute Baron de Fanzini to London, to find the next sister Imogen, who has been arrested by a Constablefor indecent exposure and finally the Alps, to find Yvonne, who is breaking off an unhappy relationship with Karl Von Kesser. But after decoding the message in Japan, Solo, Illya and Sandy are captured by Randolph and taken to THRUSH central for execution.

Solo and Illya find that THRUSH agent Colonel Picks has developed exploding apples, which will be used to trigger a nuclear stockpile. Nina Lillette, a pretty hillbilly girl, latches onto them for excitement. Illya joins a picking crew at the farm, but he is buried alive in a tunnel with the volatile apples.

President Nasasos Tunik visits Paris. His assistant, Malanez, is determined to persuade the president that the French are his enemy, and arranges for various embarrassing and insulting incidents to occur. Solo and Illya are assigned to see that the visit goes smoothly, but Tunik falls in love with Candyce, and Malanez plans to disgrace Tunik by framing him in a plot to steal the body of Napoleon from his tomb.