Based on the life of a real boy, it tells the story of Charley Goddard, who lies his way into the Union Army at the age of 15. Charley has never been anyplace beyond Winona, Minnesota, and thinks war would be a great adventure. And it is--at first--as his regiment marches off through cheering crowds and pretty, flag-waving girls.

But then comes the battle. Charley screams, "Make it stop now!" disbelieving that anything so horrible could be real. Paulsen is unsparing in the details of what actually happens on the battlefield: the living men suddenly blown into pieces, the agony and fear, the noise and terror, the stinking corpses. After many battles, Charley is wounded and sent home an old man before he is 20, his will to live destroyed by combat fatigue--leaving him with a "soldier's heart."