Shinzanmono S00 E01 Akai Yubi

A 7 year old girl is found dead in the local park's toilet. Kaga Kyouichiro, who was asked to find the girl, and his cousin Matsumiya Shuhei who's assigned to investigate the murder case, have to work together to crack the case. Their evidence lead them to the Maeharas, a family with parents, a son and a senile grandmother.