On February 19, 1942, President Roosevelt signed Executive Order 9066, which forced 120,000 people of Japanese descent from their homes and into ten internment camps. Half were children. Heart Mountain, in Wyoming, was one of those camps. Finding Moon Rabbit is the story of one Japanese American family held at Heart Mountain. The story is told from the point of view of the family's youngest daughter, Koko. While Koko, her sister, and her mother are held at Heart Mountain, the father is incarcerated at a special prison camp in Santa Fe, New Mexico, where suspected Japanese American collaborators have been placed. Not much evidence was required. Koko's one desire is to see her father again, and until that time, to at least receive a letter from him. Finding Moon Rabbit contains a number of original, contemporaneous sketches of the camp and camp life, along with other historical documents such as newspaper articles.

It's spring, 1943. Koko's ill mother and older sister have survived their first harsh winter behind barbed wire. Spring offers renewed hope that her father will be joining them soon from Camp Santa Fe in New Mexico. When Koko learns she could greet his train as a Girl Scout, she signs up. But a Girl Scout is expected to follow rules. When an MP catches Koko hopping the barbed wire fence, she promises her mother to follow the rules of camp better. Joining Girl Scouts helps steer her from trouble, but when she learns that her father is really a suspected spy, she searches for a way to endure the hardship of confinement-and face the awful truth that her family may never be reunited. But with a little luck and a letter, Koko's determined to not give up hope.

There were ten main internment camps located in the United States during World War II. California, Arizona, and Arkansas each built two camps. Idaho, Utah, Colorado, and Wyoming each built one. Heart Mountain, Wyoming, is between Cody and Powell City.

The War Relocation Authority (WRA) ran Heart Mountain from August 1942 to November 1945. More than ten thousand people lived there. Each housing block held 24 barracks buildings, two mess halls, two buildings housing latrines and laundry facilities, and two recreation buildings. Kids started school on October 5, 1942, but there were few books and little furniture. A chalk board was a piece of plywood painted black. Before the schools were built, or any activities organized for the children, parents formed Girl Scout troops. Like for Koko in the story, belonging to Scouts helped girls and boys endure the difficulties of incarceration. By the end of 1943, there were 743 registered Girl Scouts throughout the camps.