Secrets of the Dragon Sanctuary

Secrets of the Dragon Sanctuary is a fantasy novel by the American writer Brandon Mull, published in 2009. It is the fourth book of the Fablehaven series.

Two hidden artifacts have been found and three are still missing, and each of them matters because the five keys together open the great demon prison. The Society of the Evening Star is pursuing the remaining talismans relentlessly, and more of the preserves are being destroyed as it goes.

Reading in Patton's Journal of Secrets, Kendra discovers the location of the key to the vault that holds one of the artifacts. Recovering it means that the Knights of the Dawn have to enter a death trap: a dragon sanctuary called Wyrmroost. The attempt cannot go ahead at all without first stealing a sacred object that the centaurs guard with great care.

The novel follows the race to gather the keys, and it raises the questions the rest of the series turns on: whether the Knights of the Dawn can survive Wyrmroost, who is in a position to stop the Sphinx, and whether Vanessa can be trusted to help them. It is followed by Keys to the Demon Prison.