I went into the session last night not sure exactly what would happen, but I had several ideas. I knew I was going to punish them severel, but I left room for them to save themselves. I'm rather pleased with the way it turned out.
Because of logistical issues, only 3 of the 5 players were present last night. Two of these 3 PCs had the least bit of involvement in the whole attack; the third was responsible for the fireball that killed 5 minor nobles).Their weapons were confiscated and they were split up and interviewed individually to maximize their sense of solitude and helplessness.
One PC proclaimed his guilt but maintained that it was all for the greater good. One PC tried to weasel her way out of her responsiblity in the attack, claiming self-defense to a perceived threat. The third PC sang like a canary and told everything to the Captain of the Guard. He also gave some good leads that the captain could follow up on, and the captain (who is a fighter/paladin) was convinced enough to check up on some leads. Meanwhile, the Sea Lord bluffed his way past the interview with the Captain of the Guard and had the werewithal to cast undetetectable alignment when he was taken into protective custody.
When their attorneys showed up, they were encouraged to lie about what happened -- "You were under a magical compulsion and forced to do things you normally wouldn't do, right? And make sure you tell the judge you won't rest until the real culprits are caught. They always go for that line." The attorneys were appalled that the PCs refused to lie about their involvement. "Well, if you really did these things, there's not much we can do to help you," the attorneys told them.
The PCs were berated repeatedly for their actions first by the Captain of the Guard then by the judge. The main themes were "death of innocents" and "you can't take the law into your own hands" and "law and justice must be maintained." The list of charges was as long as my arm. The PC who sang asked the captain if he had found any evidence to back up his claims. Without answering the question, the Captain of the Guard, who presented evidence against them, explained to the judge that he believes the PCs think they are telling the truth (in their claim that the Sea Lord is evil) but they are "paranoid, delusional, sociopathic and obviously have been mislead at many turns by those they think they can trust." The PCs agree that he was right on the money. The captain then called for leniency; he recommended exile from Freeport.
Ah, a light at the end of the tunnel, they thought.
The judge was having none of it. "I sentence them to execution by hanging at daybreak tomorrow."
So the PCs were taken into custody, sent to the dungeons of the Fortress of Justice, and waited out their last day. At sun-up the next day, they were hanged for their crimes. They took it all very well, I might add. They knew it was what they deserved. The Captain made a statement to all the people gathered to watch the hanging -- which included the families of those killed and many who were attacked at the ball -- then signalled to the hangman. The PCs dropped and were slowly strangled to death on the gibbet.
Several minutes went by as it sunk in that they were dead, then I started with each PC individually. They awoke to an oppressive blackness and heard a voice tell them, "Shut up. You're dead." One player said, "Oh crap, we better not be being buried alive." The Captain of the Guard, as he pried open each coffin containing a PC, told them that they died for what they did. Now they have been enlisted by him as secret weapons to finish what they have started -- stop the evil Sea Lord's plot without destroying the peace and stability of the city. He had found evidence of their claims after all, but he also knew they must be punished for what had happened. He told them basically, "You died, now your slate is clean. I can't use my position to openly fight the Sea Lord. You are secretly opposing the Sea Lord's plots. Make sure those you attack from here on are guilty. No more deaths of innocents. If you have to die again for doing something stupid, then I'm willing to have that price paid."
I called the session there. I'll have to deal with the other two PCs later. Their fate is in their own hands, but I doubt either will be as lucky.