Book The Secret of Secrets — Dan Brown

Accompanying celebrated academic, Katherine Solomon, to a lecture she’s been invited to give in Prague, Robert Langdon’s world spirals out of control when she disappears without trace from their hotel room. Far from home and out of his comfort zone, Langdon must pit his wits against forces unknown to recover the woman he loves.
But Prague is an old and dangerous place, steeped in folklore and mystery. Little can Langdon know that he is being stalked by a spectre from that dark past. He must use all of his arcane knowledge to navigate a shadow city hiding in plain sight, a city which has successfully kept its secrets for centuries and will not readily give them up...
Dan Brown returns with his first novel in more than eight years - guaranteed to have you at the edge of your seat. This time, Robert Langdon is up against a deadly conspiracy that will test him to the limits - and take him to the edge of losing everything.