Description
The police think it was an assassination attempt on the infamous businessman Balthazar Blaise, but Isaac and Hattie realise that something very different is going on when they discover a boy taking something from the archives before vanishing without a trace.
As they investigate, Isaac and Hattie are pulled into an underground world, searching secret and forgotten places for a stolen letter, a missing sister and a map that will unearth a long buried secret …