It is January in the year 2113, and after a long journey through the cold, dark outer solar system you have arrived at Pluto as it swings out to its greatest distance from the Sun.   After spending some time on Pluto itself, you decide to explore Charon, Pluto's large, icy moon.   As you scan its surface, you are surprised to find a large house built atop a mountain at the head of a valley.   Your curiosity has brought you this far, so you decide to investigate the mysterious mansion, which you can find no mention of in your records.   While landing at the docking port, you notice that there appear to be lights on through the windows, and the airlock operates flawlessly as you enter the house.   Upon exiting the airlock, you find yourself in a small foyer with a welcome mat and large, elaborately carved oak double doors.   Attached to the door you find the following letter, handwritten on dry yellow paper that appears to have been there for quite some time.