Synopsis: When a thick wave of fog rolls through London, visibility in Heathrow Airport drops to zero. With all flights canceled, inept bus driver Percy Lamb has the task of driving stranded passengers to an unaffected airport. Lamb has quite a few interesting personalities onboard, including the boisterous Miss Cynthia Beeston and an innovative stewardess. But Lamb is carrying more than passengers -- he's unknowingly transporting stolen goods.