As the United States prepares to enter the First World War the family of Peter Olaf is secure in their resort home in Northern Minnesota. But then Christian, the oldest of the sons, is dumped by his girlfriend and decides to enlist in the Canadian air force. In less than a year twin brothers enlist in the fledgling U.S. army. Very shortly all three are in France, Christian is flying a fighter, Sven is driving a Renault tank and Charles is leading an infantry platoon.

But then, the army decides to hire men who are capable of running sawmills in France to supply our forces with lumber for the military infrastructure it desperately needs. Peter is running short on cash because people are buying war bonds instead of vacationing so he talks his wife, Sarah, into letting him go to France.

There are many tough battle situations before Peter is reunited with his twin sons, but they are, at wars end. At loose ends while waiting for shipment back to the states the three go in search of Sarah's lost relatives in France, and with the help of a friendly British cattle buyer they find them. Then with he help of a career U.S. sergeant they hunt for Christian who was badly injured when his plane was shot down and crashed in a river. They find him at an army hospital in London where he is recovering nicely with the help of a pretty nurse.

Eventually all the men return home and try to adjust to civilian life. Mostly they succeed, but each brother has a separate story.