Two Americans in France enlist during the war; but one has married a German woman who is accused of being a spy. A preacher suggests the war is like the deluge.
People build towers and worship money. In 1914 on the Orient Express a conversation discusses what has replaced God, and a minister (Paul McAllister) warns them. A bridge is destroyed in a storm, and the train wrecks. Travis (George O'Brien) carries Mary (Dolores Costello) to a lodge. His friend Al (Gwynn Williams) drinks in the cellar while Travis gets into a fight with Nickoloff (Noah Beery) over Mary. Russian soldiers tell them that war was declared, and they want the German Mary.
Travis, Al, and Mary are in Paris. In 1917 Al tells Travis that he has enlisted. Travis says he plans to marry Mary. American soldiers arrive, and Al marches with them. Travis tells his wife Mary that he must go. After Travis has become a soldier, he finds Al. Travis says that Mary has not written back.
Travis and Al are in a trench and are ordered to attack. Travis throws a grenade at a German machine gun, but he finds that Al is wounded. Al says he will see him in heaven and dies. Mary entertains soldiers in Belgium, and the Russian agent Nickoloff recognizes her. He demands that she meet him at one. Nickoloff catches Mary with a suitcase and has her arrested as a spy.
Mary is about to be shot by a firing squad when Travis recognizes her and stops the others, saying she is his wife. As the officers are deciding, shells hit. Travis helps Mary, and the minister says the war is like the deluge.
King Nephilu (Noah Beery) of Akkad orders the sacrifice of a virgin next month, and the poor are given a feast. Noah (Paul McAllister) and his three sons are working. Miriam (Dolores Costello) is in love with Japheth (George O'Brien). Drunk soldiers see her and take her for the sacrifice. Japheth struggles forward and tells Nephilu not to do it. Nephilu sends Japheth to be blinded and work in the treadmill.
On a mountain God tells Noah that a flood will come and to build an ark for two of each animal. They work on the ark and wonder about Japheth. People make fun of the ark, but lightning and fire scares them away.
Nephilu at a festival prepares to sacrifice Miriam. Wind blows the gates open, and Noah tells them to repent. Nephilu orders Noah taken, but the gates close behind him. The archers fail to hit Miriam. Lightning causes destruction, and rain falls. Animals come to the ark. People try to get to the ark but are washed away. Japheth prays to be directed to Miriam. He walks and hears her call. Flash floods destroy people. In the ark they tend to the animals. Japheth regains his sight and carries Miriam into the ark. Others are drowned. Noah points out the rainbow of the new covenant.
Travis and Mary learn that the war is over. The minister says that war is now an outlaw.
The closing line makes a powerful point that although
war has not been abolished yet, it has been outlawed. The making
of this film provided a lesson because, despite the warning of
a cameraman who quit over the issue, three extras were drowned
and others were seriously injured during the flood scenes.