Langdon is hired to find a man who answered a classified ad and then disappeared into thin air. And then a second person vanishes. What starts as a couple of simple missing-person cases quickly spirals into a diabolical world of witches, wiccans, and wendigos.

"You ever hear of the Church of Satan?" Jewell asked.

There was silence around the fire. The flames danced and flickered, casting shadows in the dark May night. Langdon took the bottle from Richam and poured himself another...

Bart, the dour but poetic cop, is back, even if demoted to a blue uniform. The dapper lawyer, Jimmy 4 by Four, is up to his regular philandering ways. Richam is hiding a secret from Jewell, and Chabal makes a new friend... And then goes missing.

What is going to happen during the Super Flower Blood Moon and who is the Wendigo?

This time, Langdon might be too late to solve these mysteries before the blood flows.