Bulldog Jack

Bulldog Drummond is on the heels of the Morelle gang. But when his brakes are tampered with he crashes into a car owned by Jack Pennington. With Bulldog injured, Jack volunteers to carry on tailing the Morelles. Morelle himself (Ralph Richardson) becomes suspicious of the proceedings and plans a kidnapping. When all are trapped on a driverless tube train, who, if anyone, can save the day and also catch Morelle?