On the day William and his family move into the parsonage in Plaintown, Kansas, he meets two boys who will also be high school freshmen. Clive is immediately hostile, introducing him as "Silly Willy" and "Preacher's Brat." During the first week of school Clive knocks William to the sidewalk and punches and pounds on him until Jim interferes.

Jim and William quickly become friends. They share many classes, band, and lunch. On Saturdays, they often go fishing. Late in the autumn, they camp out, and Jim demonstrates astonishing courage.

But when Pearl Harbor is bombed, war divides the town and destroys William's friendship with Jim. Caught up in the mood of patriotism that sweeps the country, William is eager to do whatever he can to support the war effort. Jim, a Mennonite pacifist, won't even sing patriotic songs, much less help the war effort by collecting scrap iron and newspapers. Clive's brother is fighting in the Pacific, but Jim's brothers refuse to carry guns.

Although William's father, the Methodist minister, preaches tolerance, Plaintown's "patriotic Americans" harass their Mennonite neighbors, accusing them of cowardice and of sympathy for the enemy. William finds himself alone and isolated, distanced from Jim and Jim's Mennonite friends, yet unwilling to surrender to the demands of Clive and Clive's friends. Drastic changes within William's family add to his distress.

This novel about friendship and courage explores the issue of pacifism against the backdrop of World War II.