As the film progresses, two thieves, Max (Bernard Fox) and Quincey (Roy Kinnear), steal the famous "Étoile de Joie" (French for "Star of Joy") diamond and cleverly hide it in Herbie's fuel tank (Herbie was fitted with an external fuel filler cap for this film - a 1963 Beetle's cap actually being inside the front luggage compartment) in order to avoid being captured by a swarm of searching policemen. But little did they know that they picked the wrong car to hide it in, because of one car that was alive and had a mind of its own. That causes them to blow every chance they get in getting back the diamond they hid in him. Because of this, and on a count of an attempt where they at one point tried to threaten Jim and Wheely at gunpoint to relinquish the car to them, an encounter from which Herbie managed to escape, and thanks to a misunderstood conclusion thereafter that Diane would have tried to mastermind the whole event. Subsequently, Herbie is placed under the protection of the French police.