The Detective Is Already Dead, Vol. 4 (manga)

To celebrate a job well done, I, Kimihiko Kimizuka, have set out on a cruise with the ace detective, Nagisa Natsunagi, and our new ally, Yui Saikawa. However, a detective's work is never done-not even a dead one's...For it seems that somewhere, on this very ship, Siesta's legacy is hidden.We didn't have the slightest inkling it existed until we got a tip from Siesta's biggest fan, Charlotte Arisaka Anderson. But no matter how important Siesta is to her, she seems reluctant to help our team in the search. She must still be angry about my year of inactivity. Just what does she want from me? I was only ever the assistant!Unfortunately, we're not the only ones looking for Siesta's legacy. After all, we're competing with S.P.E.S. and, worse yet, a pseudo-human even Siesta couldn't beat!! He'll stop at nothing to get his hands on it...