I just knew it. When I, Kimihiko Kimizuka, agreed to help Nagisa Natsunagi find her heart donor, I should've realized I was being dragged into something troublesome. Actually, I had an eerily similar feeling four years ago when I met Siesta on that plane.

Speaking of which, that was where I first met the old jailbird Bat. I brought Natsunagi to him, hoping he'd be able to identify her donor--but I never expected him to bring up that name again...
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And so, having solved my last case, it was time for me to return to my ordinary high school life--or so I thought. But apparently, Natsunagi still has business with me...What kind of trouble will she drag me into next? Family heirlooms? Spoiled idols?