The year is 1935 and Moose Flanagan’s father is desperate for a job. Consequently, he takes a job as an electrician and guard at the high-security prison on Alcatraz Island near San Francisco. The family must live on the island and obey numerous strict rules. Moose is fascinated by the fact that famous criminals, such as Al Capone, are in cells just feet beyond where he is walking. But Moose, who is twelve, misses playing baseball with his friends, and he has difficulty adjusting to his new school. He must spend much of his free time taking care of his older sister, Natalie, who suffers from autism. Worst of all, the warden’s daughter, Piper, who is constantly scheming and cannot to be trusted.