The tenth chamber - Glenn Cooper

Abbey of Ruac, rural France: A medieval script is discovered, and sent to Paris for restoration.
There, literary historian Hugo Pineau finds therein a description of a painted cave with the secrets it contains - and a map showing its position close to the abbey.
Hugo, aided by archaeologist Luc Simard, goes exploring.
They discover a vast network of prehistoric caves deep within the cliffs.
At the core of the labyrinth lies the most astonishing chamber of all - as the manuscript chronicled.
They set up camp with a team of experts to bring their find to the world.
But they are drawn into a dangerous game as one 'accidental' death leads to another.
Someone will stop at nothing to protect the enigma of the tenth chamber...