TL;DR: Not only was our latest NPC not who we thought she was, it turns out she literally wasn't who we thought she was.

It's a long story, I'm sorry! This isn't even half the detail.

A little backstory is necessary for this. Several sessions ago, our party dealt with a job involving a local theatre, which turned out to be run by a vampire who was using the patrons as snacks for herself and her banshee sister. While we disposed of the banshee, the vampire escaped. In the meantime, the current major plot arc of our campaign revolves around a criminal organisation known as the Talons, run by the Five - the Brawler, the Harlequin, the Doctor, the Puppeteer, and the Mastermind. We've already taken care of the Brawler, though we later learned the escaped vampire is the sister of the Puppeteer, and has a 'deal' of some sort with the Doctor.

Two sessions ago, we finished with the Harlequin, taking them out of play. Our next target was to be the Doctor, who we knew only a handful of things about: female, a cleric of Bane, operated out of the city's old graveyard. Before we could rest up in advance of doing that, however, we recieved an invitation to dinner with an NPC we'd recently encountered - Cerise Lamore, a noblewoman widowed six years ago who had never seemed to really recover.

We decided to attend the dinner. Though we all went in armour, Lamore gently insisted that we change beforehand, which three of us (out of a party of five) took her up on. The ensuing dinner was light-hearted enough for the most part, and we all gradually relaxed and came to trust Lamore, who we'd been initially quite suspicious of.

She told us, later in the dinner, that she wished to hire us. Specifically, she wished to hire us because she was being haunted by the ghost of her late husband, and had been ever since he had died. There were noises at night, unexplainable blood on the bedsheets, a constant feeling of fatigue. Classic stuff, really. Tearfully, she explained all this to us, and beseeched us to spend the evening in her guest rooms, so that we might experience it for ourselves.

Problem: We still needed to pursue the Five. The Harlequin had had a plot to poison the most populous areas of the city with a fear/aggression toxin, and we'd only just managed to avert that. We desperately need to rest before we take on the Doctor the next day, and there's no guarantee we'll get a full night's rest if we accept Lamore's offer to put us up for the night. With the city's safety in our hands, we can't take that risk... but we're a Good party (mostly) and with what we've heard, we can't just leave her either.

Instead, we reached a compromise. The adventuring guild we're based out of assigns a common room to each group, and personal quarters to each adventurer (attached to the common room of their group, if they have one). These rooms can only be opened by the people they belong to. It's the perfect place to bring someone who needs protecting, and we've done it before.

Lamore accepts, and we bring her back to the guild, and into our common room. There's some brief discussion of security - she seems particularly focused on the windows, but we figure, she's being haunted, she has a right to wonder how safe the place we've brought her is.

But just as we're preparing to bid each other goodnight, Cerise Lamore looks at each of us, and says, quite pleasantly, "I think this distraction has gone on long enough. Cerise should have had time to finish her experiments by now." And that is where the session ends.

Guys, we fucked up. We fucked up real bad. Turns out Cerise Lamore is actually the Doctor we were going to take down, and "Cerise Lamore", who we've just invited into our home base, is actually a vampire... And we fell for it all hook, line, and goddamn sinker. Well played, DM. Well fuckin' played.

God, I can't wait for next Sunday.