Duets
The Concept
The PC has inherited a space station in a turbulent region of space. The space station is facing economic, political, and tactical challenges that the PC will need to handle. If successful, the PC will gain in wealth and influence and could change the course of the entire region. The PC: The PC should be skilled and talented though probably not in administrative skills. The PC could be a pilot, psychic, soldier, or anything that provides the PC with abilities to allow her to survive a wide range of different adventures. The PC should be special and superior; she was chosen for managing this space station for a reason.
The Station: The size and scope of the station can vary as desired, but a good idea is to make the station quite ancient and home to thousands of individuals engaged in various pursuits. This is because while many adventures will be inspired by forces outside of the station, there should be enough depth in the station to support adventures. One or two groups or societies should dominate the station but many small groups can be present to spice things up. However, the first rule for you as the GM should be: don't detail everything. In fact, just worry about the big points and leave a lot of blanks for you to fill in later as the campaign develops.
Benefactor: The question as to who bequeathed the station to the PC should be somewhat mysterious. Maybe it was a distant relation the PC didn't even know or maybe it is a some mysterious organization that has bestowed a controlling ownership to the PC. It is best that the PC is a little uncertain why she was selected though she should learn that she was selected not on a whim but because of some reason. This is a classic of fiction and players love to feel like their PC is special and destined for something; of course they are, because the campaign is their story.
NPC Allies: The PC should begin with a NPC or two that are friends from her previous career who are loyal to her and help round out her skills. Who they are depends upon what the PC was doing before the inheritance, but having the PC bring in a few friends gives the GM avenues to provide advice and support in the challenges to come. Of course, the PC will have opportunities to add new allies at the space station and this is a way to mark the progress of the PC. Give the PC people to rescue, help, and interact with and just run with it. If the PC makes a good faith effort to do the right thing for people then the PC should get a positive response for her efforts.
Personalities: Take time to chart out some key personalities of the station that the PC will interact with. For example: who is running the station before the PC arrives and who are the key personalities overseeing aspects of the station. Union leaders, heads of engineering and security operations, the director of sentient resources, and so forth are all important. Maybe there is an A.I. program that runs the station and is loyal only to the PC who is the new owner or maybe the A.I. has to be won over by the PC. My advice is that other than a handful of key people that you draw up beforehand, simply focus on a list of names and just wing it as the PC starts exploring the station. Also always remember that if a NPC really clicks then make the character more prominent but if an important NPC bombs then have something horrible happen to that NPC. You have an audience of one so give the PC what she wants. What she really wants is something that is engaging and NPCs bomb when they don't get a reaction. The goal is not to create NPCs that the PCs like, but to create NPCs that the PC reacts to. If a PC hates a NPC then that's good -- it's a reaction.
First Adventure
The campaign should begin away from the space station with the PC at a low point. Maybe she has just been court-martialed for a crime she didn't commit or maybe she's just been between jobs for awhile. Alternatively, you can start with action: the PC is facing some goons who have come to collect for a debt. The goal though is to show the PC her life as it is now and that will be different for every character depending upon how the PC designs the character. For this campaign really anything can work. The next step is to have someone deliver the news that the PC has inherited the space station with passage provided to the station. Give the PC a chance to get some information about the station and its history on the way there but leave out a lot of key facts. It is important to make clear to the PC that the value of the space station is tremendous and that it could be the gateway to great wealth. I would make the arrival at the station revealing of the challenges to come. Maybe pirates are storming the station and the PC (if a soldier) has to come just in time to help fight them back. If the PC has a scientific background, perhaps the station is caught up in some bizarre phenomena that she can reverse. Having the PC arrive in a dramatic fashion gives the PC a cool entrance and that's what everyone wants. The first adventure really doesn't require you to delve into too much detail about the station as things are pretty scripted, but then like with any good duet you have let go of the reins and let the PC take control of the campaign.
The Campaign
My rule as a GM is simple: GMs worry about problems and leave it to the PCs to craft the solutions. Just throw a problem at a PC and then run with it, don't ever create a problem and have a solution in your mind for the problem. Just create the problem and step back and be prepared to be surprised. So for example here are some problems that may take multiple adventures or the entire campaign to solve:
1. The station begins the campaign neutral but the major regional factions want it to ally with them and are all applying pressure for it to join with one side or another. Neutrality is more profitable and probably be safer but it's hard to finesse that when the factions are using bribes, coercion, and other machinations to force the PC to join their side. The trick to running this is to understand why each faction wants the station and how they intend to win it over. You mostly have to just figure out the personality of the factions and therefore how they will approach the situation. If the PC picks a side then just figure out how everyone would react to that and run with it.
2. The station has an internal power dynamic where some people are more powerful or influential than others and the PC has the means to change this dynamic. Who does he pick as his friends and allies and who does he oppose? This is a great roleplaying scenario because it's full of mostly moral and ethical decisions. Does the PC favor law enforcement or the criminal syndicates or try juggling their influence? Does the PC favor the poorer working class or the wealthy? Does the PC favor fairness or some other ideology? The trick for the GM is to realize that in most cases there aren't right or wrong answers just decisions that produce different consequences.
3. The PC's relationships are also important. Does he have old friends or family that come to take advantage of his new wealth and position? Is there a romantic entanglement in the wings at the station? How does the PC interact with the station as an individual? This is an important part of the campaign; it's not just the strategy and decisions, but the connection between the PC and the community that is the space station. The goal is to give the PC a sense of ownership over the station and its community -- if you can accomplish that then this will be a very successful campaign.
So this is really just a quick idea for a duet campaign and really I don't claim it's very original, because it's not. However, this is a very workable formula and works very well as I have run similar campaigns in the past; from space stations to dominions in a fantasy campaign, the concepts and setup is the same. Certainly, there is a lot more work to be done for this to be ready to game and the RPG and setting would certainly influence that development, but the basic idea is a very functional one and should give you as a GM the necessary foundation to start building your very own duet campaign.

