The Most Special Agent was the first produced episode and the first broadcast episode of the television series Joe 90.
Ian McClaine's new supercomputer is put to new use by the World Intelligence Network.
In Professor Ian McClaine's laboratory he is showing Sam Loover the BIG RAT, which stands for Brain Impulse Glavanoscope Record And Transfer, when Joe enters the lab, Mac explains that he will use the machine to transfer his brain patterns into Joe. When Joe is in the ‘Rat Trap’ the large cage begins and various electronic noises and psychedelic light effects are produced as the transfer begins to take effect. When the machine is finished Joe is able to answer complex questions about computer machinery, proving the BIG RAT to be a success, but when Mac removes the electrodes from Joe's head, all this knowledge will no longer be removed.
They leave the lab to enter an old English cottage, Mac asks Sam how much the BIG RAT would be worth, Sam asks for Mac to give him twelve hours to come back with an answer. He phones back late in the night, urgently asking Mac and Joe to see him. They travel to London through the use of Mac's Air Car.
At WIN Headquarters London, Shane Weston outlines a situation upon which BIG RAT could be used to help maintain world peace…
The Russian MIG 242 is the most advanced aircraft the world has ever seen, giving the Russians an advantage over the west. The plan is for Joe to obtain a MIG 242 so its secrets can be revealed to the west to restore the balance of power.
A Russian pilot who has flown the MIG 242 is appearing at a press conference. While at the conference his brain patterns are recorded via a hidden device; the knowledge of the pilot is then transferred to Joe.
Sam gives Joe special equipment from WIN, including a specially made pair of glasses with built in electrodes which can give Joe the brain patterns when he puts them on, a gun, and a transceiver.
Mac and Joe take a flight to Russia, and go to the testing sight for the MIG 242, which is the first time foreign correspondents have been allowed to see the fighter. During the sighting Joe disappears, when the guard questions Mac he says Joe is about to steal the MIG 242, and should just be climbing into the cockpit. Although the guard doesn't believe him, the plane suddenly takes off. Joe has indeed, taken the MIG.
Even though Mac is taken before the bases Commander, nobody believes that a nine year old boy stole the plane. Other MIG aircraft are sent after the stolen MIG, but Joe manages to taken down all the pursuing aircraft. When the base sends surface to air missiles to attack Joe he uses the fighter plane to destroy the Russian Air base.
When Joe lands in England he quickly leaves before he can be discovered, so they find the plane empty.
However, this whole scenario is completely made up by Shane, there is no such aircraft as the MIG 242, and there is no conflict between Soviet Russia and the west. It is just an example of how Joe could help to maintain world peace. Mac objects to this use of the BIG RAT and sends Joe out of the room. Even though they argue Mac eventually Mac eventually calms down and accepts. Joe is to become WIN’s most Special Agent.
- The initial draft of the script had Joe become the CIA's most special agent.
- A deleted scene that was filmed for the episode but cut from the episode edit, whilst on their way to Moscow, Mac explained to Joe about why Soviet authorities have allowed Western aviation experts to visit the MIG 242 factory. This remains in the episode only as a single shot of them on the plane.
- The destruction of the Russian Missile Base was reused in film Thunderbird 6, but with much more explosions and many different camera angles.