Britain has not known invasion for hundreds of years. However, with the Nazi invasion of much of mainland Europe, the future of the world rests with Britain - and not just its navy, army and air force. Civilians can also play a vital role, in manufacturing ammunition, forming stretcher parties, the A.R.P., nursing reserves, firemen, canteen workers, or simply keeping the economy going by continuing in existing jobs. Winston Churchill makes his "we shall fight on the beaches" speech, accompanied by Australian, Canadian and New Zealand troops.