Two men are on a troopship headed for England. One is a soldier, and the other a sailor. The soldier is thinking of suicide because he is hated by members of his company. The other is a sailor who finds out the soldier's circumstance and talks him into changing places with him rather than take his own life. They get their sergeant and chief to agree to the swap and exchange identities. They are both better suited for their new roles.
The soldier's new name is Alvin Adams, and he is shipped to North Africa for America's first battle of World War II. He meets a sergeant, and they become lifelong friends. They go through every major engagement in the war. After the war, they become part of the newly formed CIA and are engaged in the clandestineness of the Cold War.
The sailor, now Casey Crane, has just as thrilling of a life as he survives his ships being sunk twice. Once he is picked up by his own ship, but another time by a German U-boat. He escapes and is returned home. Casey and his chief become close friends as they go through harrowing events together. Casey marries his chief's daughter, which adds spice with a love story. Both have eventful careers and keep up with one another.