Misshitsu no Hisoka na Hoshi密室の密かな星

Another detective agency just opened in the same building as Ukai, and the new detective is his old high school classmate, who insists on helping Ukai despite his protest. His classmate has always been standoff-ish back in school, so is there an ulterior motive why he's showing up now? --------- A new detective has set up an agency right next to Ukai's own and it turns out to be none other than his old high school classmate, Kondou aka Chikamichi. Easily eluding all of Ukai's protests, Chikamichi by bit helps with Ukai's commissions until he starts to nonchalantly begins to stay around Ukai. Back in high school,Chikamichi had placed a bit of distance,between Ukai and himself, which shocked Ukai a bit. What could be the reason for Chikamichi's reappearance in Ukai's life...?