[RPG] Dealing with PC that constantly lies to NPCs


I have a player playing a rogue in her first RPG, and she is constantly lying to NPCs. She says it is one of her character flaws and I like that she is playing the character to the fullest, but she also almost always succeeds on deception and persuasion rolls. This often means that the party ends up discarding numerous plot hooks—in one instance she convinced the rest of the party to leave the conversation before lying to an NPC and torpedoing the part of the session I had prepared most for (we were able to pivot and find another plot hook).

For example, after encountering a group of bandits in the wilderness that seemed to have some sort of magic item, an NPC in a tavern asked if they had seen anything strange, and described the bandits to a tee. Before anyone else had a chance to respond, she lied to the NPC and succeeded on a deception roll. If they were to have an open conversation, they would have learned a whole lot more about the general plot and would have been given an opportunity to join a vigilante group.

I want to encourage her to continue to play the character in the way she deems fit, but I also want to be able to write a story that has a chance of happening. How can I write around a lying PC?

FYI: Here is my outline for that session.

Best Answer

Apply penalties based on plausibility

No lie is perfect, especially in 5e. So start tracking the flaws and applying the penalties appropriately. She shouldn't have an easy time convincing people that she's a God, for instance.

Apply penalties based on reputation

She lies a lot. That means she's left a wake of people who believes she's a liar, because they fact-checked her and discovered she was lying, eventually. The more her reputation as a liar grows, the more penalties she gets.

Write plot hooks she wouldn't want to lie to avoid

If she's lying to avoid plots, this is at least likely and partially because those plots don't interest her character. Adding plot hooks that DO interest her character will hook her interest, making her chase your hook, rather than have you chasing her with hooks.

Write plot hooks that anticipate her lying

This can be done several ways, such as with General Tarquinn's book of procedures in OotS, or via meta-gaming her typical type of lies and building a story that makes lying that way catch her on the plot hook. Regardless, you should be careful about doing this too much, as opposed to other options I've specified, as meta-gamey solutions feel worse than in-game solutions.