In 1861, Henry and Katie have found love on the rugged Maine coast. He builds boats. She wants to teach school whenever her family duties relent. Their hearts are light and the future looks bright. Then America explodes in civil war.

At first surprised by Katie's anti-slavery feelings, then persuaded, Henry enlists in the 20th Maine Infantry, fated to become a legendary regiment in the Union Army. Staggering through a dozen brutal battles, including the desperate defense of Little Round Top at Gettysburg, he rises to sergeant. Katie, working on short-term teaching contracts, organizes neighbor women to make warm items for Maine's men in uniform. Quiet letters between Henry in army camps and Katie at home strengthen their love. Finally receiving a brief furlough, he hurries home for a rushed wedding and precious hours as man and wife.

But history's grip is fierce.

A ghastly battlefield wound ends Henry's war. Katie nurses him through a long recuperation, but they cannot agree—should they return to Maine or join America's mad flight westward? Ultimately transplanted to booming Chicago, little goes right for them in that overnight metropolis, which will test their strength and commitment as never before.