It is unknown how the crew of the Vespucci 7 attracted the curiosity of SIS/TR, but it is actively attempting to being order to the natural chaos human life creates. Part rescue mission, part resources discovery, A Rare Geometry is unlike anything your players have ever encountered. A clever crew can even discover SIS/TR’s unique refining abilities, allowing them to craft odd items from its system.

A Rare Geometry is an 80+ page book with expanded rules and stats for use with the SIS/TR entity, well as a vicious starship adventure written by Justin Sirois and George Holland: 

25 rooms and thousands of ways SIS/TR can attack, infect, and hack their way through your party. SIS/TR is already a puzzle players have to solve — the ship functions as a puzzle within a puzzle as SIS/TR consumes resources, manipulates rooms, and broadcasts horror throughout the captured ship.

Mothership® is a horror game for mature audiences.