Professor Loftus is to go Buckingham Palace to receive his knighthood but rivalry between Waring and Bingham means that his Rolls Royce is cancelled. Duncan sets out to drive him but runs out of petrol and, when Collier offers to drive, Bingham lets his tyres down so that eventually the journey has to be made in an ambulance. Since some robbers have also used an ambulance as a getaway vehicle, confusion reigns as the hospital party is arrested. Sir Geoffrey misses his appointment but they do get a reward for catching the villains.