Traces the history of the Rootes Group of factories, manufacturers of automobiles and aircraft. Shows the Rootes workshop 40 years ago; the use of mechanized equipment in WW1; amalgamation with the Humber organization; rationalization of the Rootes group resulting in decreased production costs and increased quality of products. The major part of the film illustrates the magnitude of the part played by the Rootes group in manufacturing armoured cars, trucks, bombers, and fighters during WW2.