With Claire's father still missing, cultists have unleashed Hell on earth! Something from beyond the Tesseract now threatens everything Claire has worked and bled for. There is a traitor in her midst-someone who has unleashed a trickster demigod. And her werewolf protector and his magical Stone Glaive can do little against an enemy who can blink in and out of existence. There's only one way to stop Akko Soggathoth, herald of the apocalypse, and it involves traveling the Darque dimension. If they cannot collect the haunted artifacts first, the fiend will awaken his eldritch siblings... and rip open the Nether Gate, exposing the multiverse to terrors beyond our imagining! A great match for fans of Cassandra Clare, Sarah J. Maas, Holly Black, or Stephanie Meyer.