In August 1950, the corpse of a Korean woman named Ko Soo Jeon is found in a shop in Yokohama. The cause of death was suffocation after being assaulted. It is speculated that worked at a brothel and was murdered by a guest. The criminal couldn't be identified and the case was left unresolved. In 1966, Miki, the granddaughter of the murdered woman, finds a letter from her grandmother.