Hubble and security officer Yates are shadowing a royal prince on a shopping trip to a jewellers,which coincides with the armed robbery of the shop. After Hubble has accidentally alerted the robbers to the royal presence they take the prince hostage and,as the SAS prepare to move in,Hubble is suspended. However he mounts his own rescue with a microlight and,as he crashes into the shop,disarms the villains with his toupee.
Hubble is abducted by Dana and Kagan, the couple whose assassination attempt on the queen he accidentally foiled. They leave him bound and gagged in a basement whilst they head off to a Royal visit in Oxford and another try. After freeing himself and inadvertently crippling Yates, one of the rescue party, Hubble catches up with the pair in Oxford, where, once more he defeats them - despite having an arm wedged in a priceless Roman vase.
Having helped three men load things into a van at the palace Hubble is told that he has inadvertently assisted thieves in stealing valuable pictures from the Royal art collection and is charged with delivering the five million pounds the criminals demand for their return. Handcuffed to the brief case containing the money he is taken to a farm where he meets the mastermind behind the heist - Sir Ambrose Hamilton,the Surveyor of the Royal Pictures. This leads to a shoot-out in an ice cream van and another accidental triumph for Hubble,who literally remains cool ...
Because MI-5 can't be trusted to ferret out a leak in Downing Street 10, royal bodyguard Hubble is sent in. He goes undercover cross-dressing as the new cleaning lady. His incessant absurd theories drive his superior into despair. Finally, flirtation from the fiend with 'Sandra' accidentally exposes him.
Hubble is assigned to escort a royal princess to a hen night at a Devon hotel,where he annoys the guests and loses his charge,ending up being stuck on the moors all night. Next day,whilst driving the princess, his car brakes fail and he assumes somebody is out to kill him to get at her. He is partly right - a colleague he has pushed too far is about to try and consign him to a watery grave,though,being Hubble,he will survive to gain more undeserved glory.