My original plan had been ...
Well, if anyone's interested still ... The main plot of my sequel was not going to have the same cast. (This is a much revised version of my early plot) I felt this was the only way to preserve the game's integrity and freshness. However, the chances of Miles and Cora coming back was not an impossibility for me. My plot had involved the eventual exploration of Mars as a possible water source besides Earth. Earth has nearly depleted it's limited fresh water supply and the team sent to extract the resource has not been heard from for a year (several months over the time designated for their arrival) ... of course I have no idea how long it would take to get there, but you get the idea. A rescue team gets sent (much smaller vessel) to investigate the delay and find that the extraction vessel had made it, but, for reasons unknown, the crew can not be found. (I have a lot more but it would spoil it for anyone who wanted to play)
If you're interested, you can e-mail me for more, but that's all I can give out without defeating the purpose of playing.