Jim and Susan decide they need a bigger family car.To test drive one they need collateral - Herbie is it, they leave him at the car lot while they take the new one for a spin. Herbie has a temper tantrum and destroys all the cars in the lot.Jim unable to pay for the damages, reluctantly has to leave Herbie inpounded until he can raise the cash. In the meantime thieves try to steal Herbie.