Gloam

Rig lives in a raider camp in the Wastes, and when Collector Mary drives off with the monsters chained to her RV, he goes with her as her assistant to free one of them: Gloam, a huge, gentle monster with a cage locked over his head who can only talk through a notebook. Mary, and the cult behind her, turn out to be far worse than a cruel collector. Captivity, torture and an M/M monster romance on the road, high spice, happy ending.