Set in the early Showa era, this story takes place in the town of Tsukumoya. It follows the adventures of a broke, debt-ridden detective with a sharp eye for detail and his unusual partner, who has the strange ability to detect lies. Together, they solve difficult cases. After the village turns against her, Urabe Kanoko leaves her hometown where she was born and raised. After arriving in Tsukumoya, she collapses from hunger, but is rescued by a poverty-stricken young detective called Iwai Souma. Impressed by Kanoko's unique ability, he offers her a job working as his assistant.