Secluded in 6x9 cells year after year with little or no human contact, three individuals in prisons across the United States experience the tedium, loneliness, and psychological despair of long-term solitary confinement. Over time, they begin to construct elaborate fantasy worlds to escape their daily reality. Through vivid, hand-drawn animation, Inside, The Valley Sings tells their remarkable stories and paints an unforgettable portrait of the power of the human imagination.