In April 1939, Victor 'Pug' Henry and his wife Rhoda set sail for Europe where he is to take up his post as a Naval Attache at the U.S Embassy in Berlin. Aboard ship, they meet General Von Roon and Pamela Tudsbury, who is traveling with her journalist father. Their youngest son Byron is abroad while eldest son Warren is also in the Navy learning to become an aviator; daughter Madeleine is left on her own in New York and as soon as her parents leave, starts looking for a job.

With the German invasion of Poland underway, Henry is called to Washington for a meeting with President Roosevelt. Impressed that Henry foresaw the German-Soviet pact, Roosevelt asks him to write from time to time on potentially interesting topics. Henry is a bit concerned when he learns from Warren, at flight school, that his daughter is living and working in New York.

Henry accompanies American banker Luigi Gianelli on a diplomatic mission to Italy to see if Il Duce will meet with a peace envoy. The Italian dictator agrees but when the same approach is made to Hitler, he declines. Meanwhile, Rhoda, bored in Berlin, is thrilled when they're invited for a hunting weekend to the home of wealthy banker Wolf Stoller. Henry is aware however that Stoller has made his fortune by forcing Jews to sells their businesses for only a fraction of their value.

At Roosevelt's request, Henry goes to London to meet with the British and provide his own personal view on their doings. However, Henry is amazed to find how efficient their radar is, and encounters Pamela Tudsbury and meets her fiancé, an RAF pilot. When he is shot down over the English Channel, Henry and Pamela spend a good deal of time together. Although he remains loyal to his wife, it is apparent that they have developed feelings for one another.

Safely back from the bombing mission, Henry begins to realize the strength of the mutual affection he and Pamela share. Any plans to spend time together are cut short when Henry is ordered to wrap up in Berlin and return to Washington for a new assignment. Rhoda takes her relationship with Palmer Kirby a step further when they spend the night together at a country inn.

With the Lend-Lease Act about to be passed, Roosevelt asks Henry to lead an informal escort of 70 merchant ships delivering much needed supplies to England. They're banking on the fact that the German U-Boats won't fire on neutral U.S. warships. After the mission, Roosevelt promises Henry command of a battleship. First, however, he must go to Moscow where he is reunited with Pamela. Rhoda goes on a week's holiday with Palmer. When the Henrys are invited to the White House for dinner, Byron asks the President for help in resolving Aaron Jastrow's passport difficulties. He also goes to Pearl Harbor where he's reunited with Warren and Madeline. Roosevelt and Churchill meet at Placentia Bay in Newfoundland. The Germans attack Russia and send them reeling as they push them further east.

Still assigned to the U.S. Embassy in Moscow, Henry saves the day when friction rises between the Russian hosts and their visitors at a State dinner. In return, Stalin agrees to greater cooperation with the U.S., and agrees to let Henry visit the frontlines. Henry isn't so sure about the visit when he learns that Pamela and her father will be accompanying him. Henry finally receives orders to command a battleship and to report to Pearl Harbor.