general outline of the sidequest i have in mind;
in a 2.5% chance when entering the wastelands, you encounter an enemy in a western getup.
you're handed a forced loss to this person (you can't really tell gender based on first appearances; also the eyes in their portrait are hidden by their hat), and you get fake-out bad ending where you get shot in the gut and begin reminiscing on your (rather short) life.
you then wake up in a bed with the person who nearly just KILLED you sitting on a stool, to which they quote skyrim ("Hey, you. You're finally awake.") before telling you how they took you to their town's hospital and how you're currently healing. The person's name is Exiye, a notably androgynous boy with a very keen eye for things (in-battle, homeboy has a Lvl 99 in senses)
You wake up with 0 stamina, and the beds in this town don't give you any stamina back. After exploring the town, you realize you have no idea where you are, so you'll have to wait on the train in order to get out of this town; and said town only gets a train out/in every week, so you're stuck waiting for a few days. Hijinks ensue, including (but not limited to if you think of something). Doing just one of these things opens up the last one on this list.
-Wooing Exiye
-Wooing Padra (town bartender, she's notably scarred. physically or emotionally is up to you)
-Meet the town whore, Khrie (has one scene for every option in the sanctum. they will make fun of you no matter which one you pick, which will be either light-hearted or destructive if you have the added humiliation fetish option in the sanctum toggled)
-Figuring out the local church is worshipping... You?
-Obtaining a voodoo doll
And, last, but definitely not least;
-Finding out that this town in the middle of nowhere is actually literal goddamn purgatory.
you take the train shortly after you discover this, and wake up in either Cassie's Safehouse with Cassie, The bedrooms of Succubus Tower with Rinny, or UNA's Hospital with Fawn, depending on which girl you've made the most progress with. You also get appearances from the minor characters if you have them unlocked! (Gin, Alissa, Nymosa and Nymph in the safehouse, Bell and Pixie in the succubus tower, and Cless, Kitty, Arlene and Sammy in the UNA hospital.)
You can visit this town again after this sidequest, but only occasionally; the Purgatory Train has a 25% chance of appearing between days, and if you miss it, you gotta wait on it again.