The Professional is the 18th broadcast episode and 19th produced episode of British television series Joe 90.
Joe 90 receives the brain patterns of a burglar, but only to help him break into an impregnable castle to obtain stolen gold.
A revolution breaks out in a country to which an aid organisation has just given $10 million to help with the building of schools and hospitals, and the new dictator, General Heppel, begins using the money to manufacture weapons instead.
An appeal is sent to the W.I.N. organisation for help in recovering the money, which is in the form of gold bullion and is sealed in the vault of the impregnable Langallo Castle.
The only man in England capable of breaking into such a place is a jailbird named Henry George Summerfield, who is serving a prison sentence, so his brain pattern is recorded and transferred to Joe 90. Joe and Professor McClaine manage to get across the border into Heppel's country and reach Langallo Castle, which is protected by electronic radio-controlled guard vehicles called Spiders. They keep a constant patrol, but Joe uses his newly-transferred skill to cut his way through without being detected, and has a proton lance to help him get to the gold vault.
He is nearly caught, but by burning his way through the vault doors and destroying the alarms as he goes, he gets to the gold. Further dangers imperil him, however, before he can take the gold to safety, and he and Mac face a hail of gunfire as the raging dictator sees his stolen gold taken away from him, speechless with rage at having been outwitted by a nine-year-old boy!