When it restarted, blinking back into existence, it brought with it a darkness that remains hidden from the mortal population. A week ago – fuelled by unimaginable hatred and unstoppable rage – a masked sorcerer killed one of those mortals.

Then he killed another. And another. With their time running out, Skulduggery Pleasant and Valkyrie Cain must work to solve the puzzles the killer leaves behind before more innocents die, embarking on a journey that will force them to deal with the apocalypse they failed to prevent the first time around.

AND MURDER. LOTS AND LOTS OF MURDER.