Nobody's Watching

It is the year 2106. Seven of the world's most elite "Executives" have escaped Earth's economic turmoil and harsh climate with a week-long vacation aboard the Polyphemos, an orbital cruiser that offers all the aristocratic luxuries of the past: fancy dress parties, cocktails and parlor games. The crew, drawn from the oppressed "Consumer" class, are on board to provide white-glove service and satisfy the Executives' every need.
But someone on board has sinister plans, and soon the parlor games give way to murder and terror. Who is the mysterious killer? Why are they eliminating passengers one at a time? And do they intend to keep killing until nobody remains?