The Treaty on the Prohibition of Nuclear Weapons took effect this January. But the world's nuclear powers have not signed up. Neither has Japan, the only country to have experienced the horror of atomic bombs. Survivors of the attacks known as hibakusha want the government to join the treaty. Some were in their mother's womb at the time. They developed microcephaly, which prevents the head from growing properly, causing intellectual disabilities. We met one such person, and heared about the brave woman who brought their struggle to light.