Once a year on Mother's Day, a charity bus service takes children from across California to visit their mothers in prison. Over 850,000 children in California have a parent in prison, nearly one in ten of the state's children. Many of these children are unable to regularly visit their incarcerated parents because remote, rural prisons are often difficult to access for low-income families. rough this bus journey, Mother's Day explores the impact of mass incarceration on an entire generation of youth.