Komadori Sisters

On a quiet spring day in the suburbs, a stray dog found the corpse of a baby. Three days after his death, the blood group of the victim was determined. Detectives Hayashi, Kaneko, Nagata and Yamagata begin their investigation, suspecting the parents of the murdered child. They use a towel, baby diapers and bruises on the baby's body as clues in the investigation. Who killed the baby?

An elderly woman, Ume Matsumoto, informed the First Investigation Department that her son Hirasaka, who runs a shoe store, had disappeared. The detectives had a bad feeling which hit the mark, an unidentified drowned body is identified as Hirasaka. Some prime real estate he owned was also mysteriously sold. Suspecting that this is a planned murder and fearing the escape of the criminal, the Department begins to investigate secretly, without creating an investigation headquarters.