Well are you asking what ideas I had in terms of plot? Honestly I think your original idea of investigating the 'Dark Planet' and rift was pretty good. However, since of course there needs to be some sort of sinister force at work we'd either need:
- a person(s) to RP as the 'darkness' and any characters that entails
- at least one person playing another role has to dictate what the darkness is actually doing.
Did you have in mind how you were going to run this RP back as it was initially stated? In any case I loved the idea of having marines or special forces characters team up with war criminals or scoundrel from the Dark Planet to figure out what is going on. We could all be in tight quarters abort one space craft where personal space is bound to be violated. Aside from that there is plenty of room for adventure within the plot.