 As an inmate at Leavenworth prison, Robert Stroud has a series of confrontations with the guards and with the other convicts. When Stroud kills a guard, he is sentenced to be executed, and only his mother s impassioned intervention gets his sentence commuted to life imprisonment, which he must serve in solitary confinement. As he serves out his sentence in boredom and despair, one day he finds a helpless baby sparrow in the exercise yard. Stroud soon takes a deep interest in caring for birds, which gives him a new purpose in life, but which also brings new conflicts with prison authorities.