This of course is a Euro adaptation of one of the great Conan tales, here reconstructed by Régis Hautière & Didier Cassegrain, and indeed, part of an excellent series:
https://www.bedetheque.com/serie-60536-BD-Conan-le-Cimmerien.html
In Red Nails, Conan and Valeria happen to bump in to each other whilst fleeing a dinosaur-predator. They're not exactly fond of each other due to past history, but they're forced to form a truce, so as to escape... well, being dinner.
Unfortunately, the only real place to flee is an abandoned... castle, or palace... weirdly without windows, or any sort of 'usual' architecture.
It gets much, much crazier from here, and is absolutely worth a read, via this particular BD, or via [the source].
Red Nails was Howard's last Conan tale, before tragedy cut short his life at only 29yo. Like most of his Conan (and other) work, it's very dark-pulpish, aspects of which the various comic adaptations only occasionally capture, IME.
