Ryouki no Ori

A series of strange disappearances occurs in Zeroshiki Department Store, one of the largest shopping malls in Japan. The management is concerned and unwilling to involve the authorities. For an unknown reason they turn to one of their salesmen, a young man named Kuniharu Shitaku, requesting him to investigate the case and find out who or what is behind these disappearances. Kuniharu must explore the mall and gather information by talking to shop managers and staff, most of which are attractive young women who may not be what they seem at first glance.

[From Mobygames]