"......Hmm. Then, Battler-kun, are you saying someone other than Natsuhi nee-san made Grandfather disappear? It'd be impossible for anyone else to do it. My receipt proved that, right? After the first time she visited that study, and until the second time when we visited it together, the study was a perfect closed room, and when the seal was broken on the closed room, he was already missing! If that doesn't prove she's the culprit, what kind of trick could they have used?!"