The Third Temple (Sam Reilly #7) by Christopher Cartwright
This is a stand-alone book. You don't need any of the prior books to enjoy it.
The book opens in 1655 when Harper Smith led an expedition to recover a golden skull from a tribe in the Namibian Desert. Unfortunately, he does not make it out alive, and the ship that was supposed to take him to safety - The Emerald Star - is swallowed by a sand storm and Smith is entombed with his stolen possession. However, one of the expeditionists, Thomas Hammersmith, is saved by a mysterious ghost who tells him that he wants him to survive so that he can deliver a message to his brother: "tell him he'll never get his greedy hands on it. I'd rather destroy it before I let him succeded." p 24
Then we go to 2005, Dr. Billie Swan is in Mount Ararat - the place where Noah's Ark supposedly made ground after the flood. She's with her godfather, Jeremy Follet. They were investigating what occurred in Armenia around 301 A. D. when King Tiruades III ruled the region, Legend has he went mad and was cured by Gregory the Illuminator who converted him to Christianity. She is betrayed by Follet and is captured and disappears.
Back to the present. In the Turkish subterranean city of Derinkuyu, a strange wooden placard is discovered floating in an old well. It’s covered in the script of a language long forgotten, but Sam Reilly has seen the text before. The words suggest an ancient race might still exist, and are in the process of building a new temple.
The question is – is it the same temple where Dr. Billie Swan is being held prisoner?
Narrated from the third person point-of-view, the book takes us to multiple settings and deals with a race of "Master Builders" with superpowers and longevity. Disguised as the Four Horses of the Apocalypse: Conquest, Death, War, and Famine - they are determined to guard the secrets of an ancient civilization that has clues as to a future event that could end the world as we know it. It is up to Sam Reilly, Tom Bower, and their crew to figure the clues out so that they can rescue Billie before it's too late.
An easy, fast, and very entertaining read. Highly recommended!