Based on a play by Reginald Lawrence and S. K. Lauren, a nurse's lover is killed in the war, and she vows their son will never fight.
Laura (Diana Wynyard) says goodbye to flyer Geoffrey (Robert Young). His plane is shot down in an air battle, and he is badly wounded. Laura is nurse on the operation, but he dies. Col. Edward Seward (Lewis Stone), knowing she is expecting a baby, offers to marry Laura. When the war ends, she says that her son will never take part in a war.
In 1940 young Bob Seward (Phillips Holmes) is in love with Peggy (Ruth Selwyn). Edward Seward, now secretary of state, speaks to the International League of Peace, proud of his treaty to prevent war. When Bob criticizes flag-waving patriotism, Peggy's mother walks out. Laura and Ed approve of Peggy; but Ed must go to Washington, because Eurasia has assassinated the ambassador. The president is sending the fleet, and the treaty is off. Laura asks Ed to speak for peace, but he says he must be "manly." As newspapers report war preparations, a peace rally is planned at the colosseum. Ed says war is being declared and that Bob must fly and use gas to destroy cities. Ed tells Laura it is her duty to withdraw from the meeting. Their cook is returning to Eurasia to fight for honor. Ed arranged for secret police to go with Laura to the rally. She speaks to the mothers to prevent war; but men heckle her and break up the meeting, as she is ushered out. Bob cares for her as an angry crowd gathers and throws bricks in their windows. Ed with Steve in uniform speaks for rights and pledges his family to support the war. An AP reporter took Steve for Bob, but Bob says he is will not take part in the war. Peggy questions Bob and walks out. Bob complains to his mother he is despised, and Ed insists she stop her anti-war activity. Laura says she must leave Ed, and Bob tells Ed he will stand against war too. Ed tells Bob he is not a Seward but the son of a war pilot who was killed.
War planes fly, and troops march. Already hundreds of thousands have been killed. Laura goes to Peggy and tells her about Bob's father. The city is bombed, and Laura is wounded in a car with Peggy. Bob calls Ed on a picture phone. Ed tells Laura thousands have died because they were not prepared for war with gas. Bob tells Ed he took a commission in the air corps. When he tells his mother, she asks why, saying the old sense of duty must be overcome. She pleads with Ed and cries. In the final scene Bob flies in a plane, as Laura's mother (May Robson) says women should govern, and the married Peggy says her son will not do this.
This amazingly prophetic 1933 anti-war movie showing war breaking out in 1940 has unfortunately been neglected and rarely shown. Cities were destroyed and at the end of the war by worse than gas. If the aims and efforts of people like Laura had been more widely practiced, that terrible war and others could have been prevented. Yet this story shows how their visionary ideas were ahead of their time.