Nagisa Natsunagi Still Wants to Be a High School Girl, Vol. 2 (light novel) - The Detective Is Already Dead, Ordinary Cases

The proxy detective is living her dream.All Nagisa Natsunagi wanted was to be a regular high schooler, and right now, that’s all she is. The most special thing about her is that she was too sick to come to school for a long time—but that’s all in the past now thanks to a successful heart transplant. At long last, she’s finally living the life she always wished for! Still, she can’t help wondering about her donor, and there’s a boy in town who can solve any case. Maybe he can help?