We don't know a great deal about the plot, other than the first half of the first episode. However, the Unreliable Narrator that TTG is going for is frankly awesome. They are spicing this game up more than I initially expected them to.
We're playing as two characters, and both seem like they'd be as untrustworthy as each other. One is a con artist... the other is a corporate ladder climber. Both seem like the types of people who'd lie out of habit more than anything.
But based on what we know about Fiona and Rhys... who is more likely to be telling the truth? The woman who makes her living by lying and tricking people? Or the man who is cheating his way into the Hyperion presidency?