THRUSH agents develop a new drug that will help them on their quest for world domination. UNCLE assigns April Dancer to make sure an antidote to the drug is available.
Mark Slater is asked to guard Ali Hassen, the ruler of Zalamar in Arabia. When Hassen's daughter is kidnapped, April Dancer is asked to be her double until the real daughter can be rescued.
April Dancer and Napoleon Solo work together to locate a a half-penny that contains the locale of Lisa, Vito Pomade's daughter.
Mata Hurens, a belly dancer, has an important message for Waverly. However, when she is killed in a train explosion, April sets out to find who is responsible.
The security of UNCLE is put to the test when THRUSH steals a Monotori, a device used by UNCLE agents. Waverly assigns April and Mark to get back the item before it is too late.
DeSada, the leader of the Central American branch of THRUSH, hatches a plan for world power by way of a new cutting-edge rocket. After kidnapping the designers of the rocket in order to keep the rocket's design secret, April and Mark are sent to locate the missing engineers.
When Stanley eats a microdot planted by THRUSH in a piece of cheese, April and Mark must travel to Denmark to retrieve Stanley.
A doctor's life is put on the line when he invents a serum that would enable the minds of dead people when given to a living relative. A cult, UNCLE and THRUSH are all vying to get their hands on the serum first.
Professor Antrum, who has been researching the locale of the lost city of Atlantis, is kidnapped by THRUSH. Mark and April are sent to find them, but wind up kidnapped themselves.
In the South Pacific, THRUSH completes their plans to take over countries in the area for a smuggling operation. Mark is able to get his hands on their blue prints, but April soon finds herself imprisoned by a ruler of a remote island.
April is attacked by an eagle as a THRUSH agent tests a new invention.
A circus owner, who earns money by doing criminal acts, has is fraudulent acts exposed by an angry countess. The owner kills the countess out of revenge, but Mark and April are soon on his trail.
Gambler Joey Celeste offers to inform on his bosses to UNCLE, but soon finds that he himself is the target of a hitman. April must get Celeste from Italy to UNCLE safely.
UNCLE must protect the Topango jewels. But when April is drugged and Mark goes missing, the mission turns out to be more difficult than expected.
A man offers Professor Quantum anything for his newest invention, the Light Variator. However, when April begins working as a lab assistant in order to investigate undercover, the professor falls for her.
When a crime syndicate puts out a hit on April, the hitman has ideas of his own and forces April to be a part of his harem.
Dr. Vladimir Toulouse invents a pill that provides super strength. He threatens to release it to an army that would destroy the world unless UNCLE gives him a large amount of money.
Thief Horsh is captured by April and Mark. However, he soon escapes their custody. When April tries to recapture him, she falls into trouble and must rely on Mark to rescue her.
THRUSH sets out to take down three sons of the King of Drublegratz so that when he passes they can take over control of the country. After one son is found dead, Mark and April are sent to protect the remaining two sons.
Baroness Blangstead invents a serum that provides eternal youth and wants to give it to the wives of political leaders. April and Mark set out to capture the Baroness.
Mark finds himself in trouble when he loses a tape containing vital information. April and Mark must find the tape before it falls in the wrong hands.
Titerian crystals are found in the Utter Anguish Gold Mine. When the owner of the mine passes away, UNCLE and THRUSH square off to retrieve the crystals.
On old gangster tries to take control of a Mediterranean country, but has to remove two people from power in order to do so. April and Mark are sent to the country to stop the gangster.
Waverly believes a French School for Civil Administrators is planning a hijack, so he sends April and Mark to investigate.
When a client of a bodyguard service is murdered, Waverly sends Mark and April to investigate.
THRUSH develops a process that disrupts UNCLE's communications. Mark is able to tape their transmissions, but is shot in the leg in the process. As Mark is taken off of the case to heal, April is assigned to it.
Waverly has reason to believe that a Japanese war criminal is active once again. He sends Mark and April to Hawaii to investigate this notion.
April and Mark go undercover as an airline stewardess and a big game hunter, respectively. Both get onboard a plane headed for the Council of World Scientists meeting, but on the plane is a substance that can cause a slow, painful death to humans.
April, who is testifying as a witness against a THRUSH agent, is threatened and is told to stay with Mark until the trial.