Den Schlaf des Todes

From publisher blurb:

A claustrophobic one-off scenario that I've run at Conception and Concrete Cow in 2011; like many of my scenarios, this is light on detail, allowing plenty of room for inventiveness and creativity, so that each session can be coloured to suit the people at the table. It's very important to read the scenario and all the characters very carefully if you're going to GM it though: there are details embedded in the document that will prepare you in advance for many of the questions that may arise in play.
By the way, the title translates as "The Sleep of Death."