Sadako was born in Japan on January 7th, 1943. She was destined to be a runner. When Sadako was only 2 years old, America dropped an atomic bomb on Japan in an attempt to end World War II. Sadako survived the bomb, but unfortunately, she later developed a disease caused by the radiation, called leukemia.

Sadako participated in the bamboo class race and won. She was selected for the junior high race tournament and was very happy. However, one day, Sadako began experiencing the effects of leukemia; she felt dizzy and collapsed. When she was sent to the hospital, her friend gave her a golden paper and told her about the 1,000 paper cranes.

In the hospital, Sadako met a boy named Kenji. He was nine years old and also had leukemia, which he had inherited from his mother. Sadly, Kenji passed away the very next day. Sadako managed to fold 644 paper cranes. One day, when she could barely open her eyes, she said, "How beautiful the paper cranes looked." She then closed her eyes and never woke up.