Dinner at Deviant's Palace — Tim Powers

A generation after the bombs wiped out Los Angeles (along with most of the rest of the world) survivors have trickled back to set up life in the ruins. Times are hard. People take whatever solace they can--from each other, from new drugs, from perversions only whispered about in the infamous private club called Deviant's Palace. Some turn to the mysterious religious cult formed by Norton Jaybush--and once they are taken into that group, not one is ever seen again.

Greg Rivas has a reputation as a tough guy. When the woman he once loved disappears into the Jaybush cult, he takes on the most dangerous assignment of his life: to infiltrate the cult and bring her home alive. What he finds at its center, when he learns at last what Norton Jaybush really is, is a horror so devastating that he will never be free of it; and the world will be changed forever....