The Doctor’s pursuit of the mysterious monsters under the bed in ‘Listen’ take him to the end of the universe and of time. Normally a TARDIS isn’t supposed to go that far but the Doctor had earlier removed the safeguards and if he can do it so can your PCs. They could also end up there, stranded like Orson Blue.
The Doctor calls the location where Orson’s ship crashed the last planet. This indicates that all other planets have likely been destroyed by entropy This world is depicted as a barren rock, bathed in a pink light from a vast setting sun.
The identity of the planet is never confirmed. It could be one that we are familiar with or it could be some far flung rock that only becomes significant because it is the last one left. This could be due to chance or it could be that this planet was specially prepared so that it would outlast everything else in existence.
It isn’t clear how long the planet has left before it too is consumed. It is stated that Colonel Pink has been there alone for 6 months. There doesn’t seem an urgent need to hurry with Orson’s only objection to staying one more night being based on his fear of what might be outside.
This could mean that the planet could continue to be the last thing in existence for years, decades or centuries. This gives you a lot of room to revisit the planet, especially if PCs want to be the last man standing themselves.
While the rest of the universe might be gone the planet could be beacon for time travellers. Pioneers, like Orson, could naturally end up there as their time machines can’t go any further forward. This in turn could lead to future rescue missions when time travel is perfected and people work out where earlier missing time travellers ended up.
There are other reasons that time travellers could come to the planet. Like the Doctor in the Big Finish audio ‘Dark Eyes’ they might just want to see how the universe turns out. At this final point they can look back and try to work out the entire history of everything.
Anticipating this time capsules or data storage devices could have been hidden on the planet. This could be the basis of an adventure, with the PCs getting involved in a treasure hunt to recover this information or caught up in the expedition of others.
The end of time could make for a good hiding place for species with time travel. PCs could encounter all types of desperate people and old enemies. We know that Time Lords traditionally didn’t come this far forward in history, making this a perfect place to hide from them.
It could be that the Time Lords restricted their time capsules because the high council had a secret base here which they didn’t want the public to know about. We know the Doctor had secretly hoped to be the last man standing so it would make sense that an egotistical race like the Time Lords would want to be there at the end.
The fact that that there shouldn’t be any other life in the universe at this point might make it desirable for races who are struggling with overpopulation and possess time travel. They could send their people to this far off period to establish a colony where they know that history won’t be altered.
As discussed we don’t know how long the planet has so this colony could last for some time. They’d have to bring their supplies as resources in the local area would appear to be very limited.
If more than one race gets this idea then this could lead to conflict. An adventure could use this as an exploration of how war is endless and futile (since the universe is dying around them).
People could come to the planet for the very fact that they want to be the last one in existence. The true victor would be the one that was there at the very moment of the planets destruction. Achieving this would also require the elimination of everyone else present.
It has previously been established that some beings were able to survive the destruction of the old universe and cross into ours. There could be those who wish to make the journey into the next reality, using this planet as their launch pad.
PCs could be tasked to prevent the wrong people from crossing over, particularly as it might give them godlike powers. This could be tricky, as the PCs run the risk of crossing over. Might they also be tempted to let their enemy go just so they don’t trouble our universe any more?
Some races might not want to physical cross over but just send across a time capsule, so that the next universe is aware of their existence and their achievements. In this way someone of our history will be forever remembered.
PCs who like a challenge could try to save the universe in its dying moments. Is it possible to reverse the entropy and bring life back to the universe? Like the Doctor could they give it a whole new life cycle?
This might through off the natural order. Do they have the moral right to prevent the creation of the next universe?