This was an interesting book but I cannot say its good. The ending is weak.
Basically, Ian Graham, a newscaster who recently lost his job, takes on a position of doing investigative journalism and his first report is from Rosyln Chapel, a historic chapel. While in Roslyn, Graham hears a humming sound that no one else hears. While talking to Rob Madison, a guide, he learns some of the history of the chapel and somehow hits his head. When he awakes, he has been sent back in time to the body of his prior self, a warrior/templar in France in the months before the Templar Order is slaughtered by the King of France and the Pope. Graham travels in France between various cities going to churches in a pilgramage to save Templar treasures and find the secret to the song that he alone hears. On his pilgramage he is accompanied by people who look the same as his friends in the future -- so Rob is there as a Templar guide, and Roddy his agent is there as a Stonemason, and various Saints and his Gran, long dead visit him in the various churches providing him with clues to save himself from people seeking the same treasures and to stop him. As a treasure hunt the book seems interesting -- the historical fiction seems spot on, and the tales of the various churches and the inside of same and the secrets in the vaults and all are impressive, but the end of the book seems to me forced as is once Graham gets to where he can get home what can be done with what he discovers.
At one point Hunt talks about the Nicholas Cage movie -- National Treasure or its prequel, and while I know this is literature I think some more action in that vein would have done this novel some good.
Read it for the history and the time travel -- the journey is interesting. One wishes the ending was as.