The secretest secret of all is about to be made unsecret …

Renowned Harvard Professor Richard Wangley is enjoying a relaxing visit to Prague, city of magic, alchemy and labyrinthine underground tunnels. But when his girlfriend disappears hours before she was due to publish an earth-shaking manifesto and the latest of a series of hideous murders points towards him, Wangley must go on the run to prove his innocence and prevent a catastrophic threat to the entire world.

Far from home and armed with nothing but his wits, his knowledge of ancient symbolism and a cream turtleneck that does nothing to hide his middle-aged spread, Wangley must navigate a city where every cobblestone could be a clue or a potential trip hazard.

As he races against time and a grotesque spectre closes in, Wangley finds himself in a labyrinth unlike any he has previously navigated. Except for that time in Paris. And Rome and Florence.