Jethro has three brothers, Bill, John and Tom. John, Tom, and their cousin Eb are eager to fight for the Union in build-up to civil war. Jethro struggles with the split between them, as Bill decides to join the Confederacy. Later on, Jethro's good friend/teacher, his sister Jenny's boyfriend, Shad, also joins the Union Army. John's wife Nancy and their two young sons come to live with the Creightons during the war. Jenny's father will not let her marry Shad because he thinks she is too young.
As the war heats up, tensions arise among the townspeople. A gang of men led by Guy Wortman are angered by Bill's decision to join the Confederates. Eventually, Jethro's father suffers a heart attack, leaving Jethro as head of the house. One day Jethro travels to Newton, and overhears criticisms of his brother. While Jethro is riding back, he is warned that the critics are up to no good. Dave Burdow, father of the young man responsible for Jethro's sister Mary's death prior to the events of the story, ends up saving Jethro's life and driving the troublemakers off.
After a few months, the family’s barn is burned down and the water in the well is deliberately contaminated. Jethro finds out that his brother Tom has been killed and that his cousin Eb has deserted from the Union Army. Jethro writes a letter to President Lincoln for help and begins to look up to him as a father during the crisis. Lincoln replies, telling him that he is already working on a program to accept all willing deserters back into the Union with little punishment.
Soon after, the family learns that Shad has been wounded and is in the hospital, being taken care of by his aunt. Jenny finally receives her father's blessing, and she and Shad get married. Shad gets better, the war ends, and he, Jenny, John, and Eb return to the Mossing farm. However, at the end of the war, just when the family is reunited safely, Jethro learns that the president has been shot. He runs off but is found by Shad who tells him that he and Jenny are going to college, and that they will take Jethro with them. Jethro is filled with joy.