Kazuhisa Murakami, who is blind, asks his brother Tatsuhiko to donate a kidney to his granddaughter. When his brother refuses even to be tested, Kazuhisa begins to suspect that the man he has believed to be his brother for twenty-seven years is an impostor. He investigates the identity of the brother who returned to Japan as a Chinese war orphan.

Is the man he has trusted as his brother for twenty-seven years truly his brother?