Serial Disappearances of Yokohama Visitors Case

The Serial Disappearances of Yokohama Visitors (横浜連続失踪事件,) is a case submitted to the Armed Detective Agency.

Background
It is a series of missing-persons incidents, with no obvious connections among the victims. The victims have only two things in common, albeit minor: they don't live in Yokohama, and they walked off into thin air.