Dr Twist (Will Hay) is forced to pose on an Atlantic liner as the famous Professor Tavistock. As the professor he is asked to tutor Bertie Schultz, the precocious son of a millionaire. To avoid awkward questions about his passport when he arrives in the USA, he enlists the help of a gangster stowaway to smuggle him into the country. Two rival gangs have hatched separate plans to kidnap Bertie for a ransom demand, and inevitably the hapless Dr Twist becomes entangled in all sorts of mischief!