Several major loose ends in the campaign were tied up last night. Morton Ragnarsson (pilot - my character) and Faust (mortician - an irregular player's character) were heading through the engineering tunnels, chasing down criminals who had escaped through a jailbreak. Eventually, we find a trap door leading upwards, a branch in the tunnel the two of us were not familiar with. Taking a universal lockpicking device (also known as a "crowbar"), Morton pried open the trap door, and he and Faust lept up into the room, weapons at the ready. Waiting for them was a man in a black trenchcoat, Virgil, that they had seen glimpses of at various times on shore leave (and had been warned about), as well as Mr. Rhyze (communications officer - the other regular player's character), decked out in gleaming black armour.
The other regular PC was actually a villain!
Now, I really, really should have seen this coming. There were many signs throughout the campaign, though all of them subtle. Mr. Rhyze had started with several hundred units of currency, whereas the ship janitor (another irregular player's character) and Morton had started off with a couple dozen. There was the lack of Starfleet rank ("Mr." Rhyze), but I had dismissed that as being like Mr. Sulu. As well, my character doesn't have a hard-and-fast rank, apart from "pilot". There were also a number of other indicators I failed to pick up on.
But when it comes down to it, why should I have picked up on it? I've never experienced anything like this before. Previously, ever other game I've played in since I was in elementary school had involved a party of heroes. Having a character in the group who will eventually betray the station is interesting. First, it means that for the past year (roughly 30 adventures - we don't always get to play weekly) one half of the two regular "heroes" was not in fact a hero, but was directly working against many of the things my character was doing! But with his death (Rhyze got sucked out into space), it changes the game dynamic again: we now have fewer dangerous characters, which means that Morton (my character) will probably be at the front of most of the battles from now on.
So, I have to ask: who else has had a situation like this in which one of the PCs actually turns out to be a major villain? Was it in a short adventure, or a long campaign? How did it affect the threads of the game? Did you like it or not?