Toudou was the only one who managed to find his niece Tsubasa, who had survived a terrible murder and was hiding in the closet. Now, four years later, Toudou and his father are taking care of Tsubasa, who has stopped speaking, while Toudou still works as a detective. His new partner is Saeki, a young woman with a bright future. As they work together to solve murder cases, they will also have to confront their own difficult pasts.