A retired judge who regrets those criminals he had to let get away arranges for Brett and Danny to meet, and then gets them arrested so that they have the choice of either helping him out in his fight against crime or staying in jail. Their first assignment is to locate an heiress by her heart-shaped birthmark.
Danny and Brett must discover whether or not Gold Napoleon coins are the originals, or replicas as a coin dealer claims them to be.
Danny and Brett try to help a girl whose "long lost brother" has suddenly appeared, cutting her off from her inheritance.
Brett's family mansion seems to have been restored without his knowledge, and taken over by strangers. To find out why, he pretends to be the actor they have hired to impersonate him, and ends up helping the Prime Minister.
When the Judge tricks Brett and Danny into identifying a dead woman found floating in the waters of the French Riviera, they end up investigating an international stock swindle.
Danny runs into political intrigue when he discovers the dead body of a reporter, then can't find it until it turns up in a car crash hours later.
After Brett loses seven days, Danny thinks Brett is acting strange but Brett thinks someone is impersonating him. They both can't be right.
Danny has to go on the run from enemy agents after his gambling winnings at a Brighton casino turn out to be part of a communist plot to pay off spies when they use the right code words.
It seems that everyone including a former Nazi wants a German Eagle statuette, and they think that Danny is the one who has it.
An childhood friend of Danny's from the Bronx turns out to be a hit man hired to kill an American labor leader on holiday at the Cannes Film Festival.
While out camping at Brett's family estate, Danny gets chained to a brief case which he can't get off that contains a bomb.
In order to catch a war criminal, Danny must impersonate the kidnapped Brett, but how will he explain an English Lord with a Brooklyn accent?
When Danny and Brett find the decade-old dead body of a scientist in a crashed plane in the Scottish Highlands, several women claiming to be his daughter offer them various inducements to part with the formula they found.
When Brett's plan to capture a traitorous British spy by pretending to be him results in his own capture, Danny enlists the aid of one of Brett's relatives to rescue him.
At a London airport, a gang of crooks who are planning a bullion heist mistake Danny for a criminal mastermind when the man's suitcase accidentally ends up in Danny's luggage cart.
Danny buys a `handy man's special' cottage in England and discovers that his neighbors are into the occult.
Trying to open a travel business, Danny and Brett encounter a New York hoodlum who needs to be smuggled out of Italy after he killed an Italian gangster.
After Danny is accused of kidnapping his blind date, a rich man's spoiled daughter, Brett and Danny decide to help rescue her from the real kidnappers but have problems keeping her rescued.
Brett wakes up one morning and discovers that he got married the night before.
Seeking sanctuary with his old friend Brett is a spy who plans to publish his memoirs, which contain the name of every NATO, SEATO, and ANZUS agent.
Brett's relatives are being killed off one by one, so Brett and Danny decide to find the killer before he gets to Brett.
To retain the family jewels, an elderly Russian duchess must present proof of her marriage into the Russian Royal Family, which she says she can do with the help of a journal kept by one of Brett's uncles.
Brett and Danny both end up wooing an heiress after they are asked to break up a romance between a her and a gigolo who is courting her.
Mission: Monte Carlo is a "movie" comprised of two episodes from the 1971 British/US TV series The Persuaders - which accounts for the presence of Basil Dearden, who died that year. The only element that the two hour-long episodes truly have in common is their setting: Southern France's Cote D'Azur. The discovery of an exotic dancer's corpse leads playboy secret agents Danny Wilde (Tony Curtis) and Lord Brett Sinclair (Roger Moore) on a merry chase after a gang of stock swindlers. This storyline is expanded with scenes from a second Riviera-based Persuaders installment, written by Val Guest, wherein Wilde and Sinclair pursue a contingent of gold smugglers.
Life is never dull where Lord Brett Sinclair and Danny Wilde are concerned. But who would expect dire danger, hilarious though it may be, to face them in one of Brett's baronial homes? Even more unexpectedly, murder and black magic take place when Danny decides to own his own little piece of England and buys a tumble down old cottage. The old mansion, Greensleeves, has been in the Sinclair family for generations, but has been unoccupied for a long time except for an aged butler named Moorehead. It is only by chance that Brett discovers that it has been restored without his permission. He and Danny decide to investigate and, entering through a secret tunnel, find a letter addressed to a theatrical agent asking him to an actor who resembles Brett. Brett promptly poses as the actor and gets the job of impersonating himself. Danny and Brett have a lot to overcome before Danny can enjoy his little piece of England!
Life in the fast lane becomes deadly for Wilde and Sinclair when the mob tries to "fix" the sport of high-speed racing. Wilde then finds himself mixed up with lady luck and a network of communist killers.
