I'm sorry, but I don't have any information about a book called "Nineteen Quiet Rooms" by Ottilie Marsh — I can't find it in anything I know, so I have no idea what the twist is, and I'd rather not make something up, especially with book club right there.

A few quick options for tonight:

- **Check the ending directly:** If you have an ebook, jump to the last chapter or two. If it's an audiobook, speed-listen at 2x. Just read the final ~30 pages.
- **Search carefully:** Sites like Wikipedia, Goodreads reviews, or BookRites/Instaread-style summaries often spoil endings — but search the exact title and you may find a plot summary. Fair warning, you'll hit spoilers if you go this route, which is fine since you're past caring.
- **Ask someone in the club** who finished it, just for the ending.
- **Wing it:** Honestly, lots of book club members haven't finished; you can listen and nod.

If you can tell me the title/author might be slightly different, or describe any part of the plot you remember, I can try to help identify the actual book. And if you want to tell me what *did* happen up to where you got, I'm happy to speculate with you about where it might go — just knowing it's a guess.