Kelly and Alexander's assignment is to find a list of Nazi war criminals before the war criminals find it. The agents discover there is no list. A little girl has memorized the names of the Nazi war criminals.
In Europe, Kelly and Scott investigate an actor who is also a spy. The actor dominates his mistress, Temple. While Kelly gets to know Temple, Scott is captured and interrogated. When Temple discovers the truth, her life and Scott's are endangered. When Temple calls Kelly to suddenly break off their developing relationship, Kelly realizes he must take action quickly.
When the daughter of a powerful British arms producer is kidnapped, Kelly, who naturally had a romantic relationship with her, immediately suspects a hoax. When her father insists on paying the ransom and rescuing her, whether she wants to be rescued or not, Alexander and Kelly get the job. However, the fading warlord who is holding her is privy to all their plans and turns out to be as philosophical as he is ruthless making him most unpredictable.
Recovering from his torture at the hands of enemy agents, Kelly Robinson travels with Scotty to Spain's Costa del Sol for a 30-day vacation. There he's pleased to meet old friend Lindy but reminders of his recent ordeal seem to lend credence to a psychologist's judgment that he's no longer the man he once was. The enemy agents now reappear, kidnap Kelly at gunpoint, and once more try to torture from him details of a top-secret metallurgical process. Scotty arrives and puts a stop to the torture by giving a written copy of the process to the agents. Having successfully...
On vacation (again?) Scotty and Kelly bump into one of their not-so-fond acquaintances, a British agent they've found thoroughly untrustworthy. Unfortunately, orders are to find out what he's up to rather than shoot him. Suprisingly, it has something to do with rescuing a poor old art lover who refuses to disclose a secret he seems to consider worth dying for.
When Kelly wakes up with with a dead Russian ballerina in his bed and no memory of how she got there, Russian intelligence presumes Kelly murdered her. The Russians plan to report Kelly to the Spanish police unless, with Scotty's help, he can prove the murder was committed by someone else.
Scott and Robinson are assigned the impossible job of keeping a particularly ornery touring comedian from embarrassing the United States. A Soviet agent along for the ride is assigned to encourage trouble. When the comedian's assistants start dying, our duo and the Russian begin a perverse version of "Old Maid", perhaps better named "Who will get caught with the dead girl."
Herbie is a man with a terrible headache, several in fact. You see he used to be a filing clerk privy to many of America's nuclear secrets. But he resigned and is now being courted by a beautiful enemy agent. The best way our favorite counter-spies could find to keep him out of her clutches is a series of concussions.
Kelly and Scott get an assignment not to their liking. They are sent to a seaside vacation spot to take out an undercover spy Karlovassi. But after meeting him they develop a friendship with the charming rogue.
Over the years, ten-thousand children have been kidnapped from a northern frontier province in Greece to be taken through the Iron Curtain. There they are brought up in state orphanages, brainwashed, and trained as agents to be later infiltrated back into Greece and used against their country. Robinson and Scott's assignment is to rescue a friendly agent involved with disrupting this child-smuggling operation but whom is now trapped behind the Iron Curtain.
Scott is ordered to get close to an African woman who has access to important intelligence about armed shipments to her country. But he is faced with an attack of conscience once he begins to develop genuine feelings for her.
A child violin virtuoso begs Kelly and Scotty to smuggle him out of communist Bulgaria so that he can live with his sister in Greece. Against better judgment they help the boy and get a nasty surprise for their trouble.
Ten days after Kelly has missed an important meeting held in Athens, Scotty finds him lazing on a quiet Greek isle in the Mediterranean. Kelly tells Scotty that he's "come in from the cold" - meaning he's quit the spy business.
While in a toy shop in Chinatown, San Francisco Kelly and Scott meet an attractive Chinese young woman named Mai Lin. Kelly is immediately attracted to her and strikes up a conversation. While showing her the sights they find it strange that she says she is from San Francisco yet has no knowledge of the most obvious San Franciscan sights...Alcatraz, Golden Gate Bridge, etc. The mystery gets deeper when they are assaulted and she is stolen away. Their investigation leads them to an ancient Chinese cult who have plans for Mai Lin.