“One Came Home” is a historical mystery by Amy Timberlake. It follows the journey of thirteen year-old Georgie Burkhardt as she tries to determine if her older sister Agatha is really dead. When the novel begins, a funeral is being held for Agatha. Though Georgie does not believe Agatha is actually dead, she secretly worries that it is true. She leaves her hometown of Placid, Wisconsin, for Dog Hollow. Dog Hollow is located eight miles past where a girl’s body was discovered in Agatha’s blue-green ball gown. Georgie reluctantly allows nineteen year-old Billy McCabe, a past suitor of Agatha’s, to accompany her.

Georgie finds Billy both handsome and annoying. She knows that he asked eighteen year-old Agatha to marry him, but her sister had turned him down numerous times. Agatha had ultimately fallen for thirty-five year-old Benjamin Olmstead, owner of the local hotel and a massive library. The library gave Agatha a window into the world and into education at a time when most women did not attend university. Georgie wondered if the library might have been the reason that Agatha wanted to marry Benjamin.

While Agatha was engaged to Benjamin, Billy McCabe kissed her. At the time, Billy was engaged to a local girl named Polly. Georgie saw the kiss and told Benjamin about it. He promptly broke the engagement. Ten days later, Agatha left town with a group of traveling pigeon followers who had followed flocks of wild pigeons to the area to hunt them. Shortly thereafter, a girl’s body was discovered by Sheriff McCabe (Billy’s father),who had gone looking for Agatha.

Georgie and Billy travel to Dog Hollow to talk to people who remember seeing Agatha. They discover the spot where the body was found, but they find no clues there. When a general store owner explains that Agatha was in the company of disreputable people who usually go to see Mr. Garrow when they pass through town, they visit Garrow Farm. There,Garrow and his wife deny knowing Agatha, but they do say that their own daughter, Darlene, has eloped. Ironically, Darlene very much resembles Agatha.

On their way back from Garrow Farm, Georgie and Billy come across Mr. Garrow’s counterfeit money operation, and Billy is captured by Mr. Garrow and his associate, Roy. Mr. Garrow breaks Billy’s ribs. Georgie shoots Roy’s thumb off. Then, she shoots the gun out of Mr. Garrow’s hand and frees Billy. She leads him back toward Dog Hollow.

On the way back, Billy believes that he's dying. So, he confesses that he kissed Agatha in hopes of Georgie seeing them. Ideally, Georgie would tell Benjamin Olmstead about the kiss. Then, the wedding would be called off, and Agatha could be Billy’s once more. Instead, Agatha refused Billy and said goodbye. Georgie is very angry when she hears the story. On the way to Dog Hollow, she runs into Benjamin and his groundskeeper, who take Georgie and Billy to town, where Billy’s injuries are treated. A posse goes out after Garrow and Roy. An account of their capture, including Georgie’s shooting, winds up in all the papers. These stories prompt Agatha, who is now living as a student in Madison, to write home to her family, apologizing for leaving without saying anything. She also apologizes to Benjamin. Georgie and her family are angry at Agatha's behavior, but they are thrilled she is alive. They forgive her.

As the novel ends, Billy marries Polly and moves to Minnesota. Agatha and her family keep in touch regularly. Georgie later finds out that the dead girl found near Dog Hollow was Darlene, who had intended to elope with her boyfriend. However, she was stopped by Mr. Garrow. Trying to wrestle her father’s gun from under some saddle bags to ward him off, Darlene accidentally shot herself. She was wearing Agatha’s gown, a gift to her from Agatha when they met during Agatha’s time with the pigeon people. Appropriately, the name on the tombstone is changed from Agatha's to Darlene's. Since Darlene dies from an accidental, self-inflicted wound, Georgie never shoots a gun again.