Consume the Spirit of Thine Greatest Enemy, in the Land of Erebus, on All Hallows' Eve ...

Harley has a game plan to stop the third ritual: infiltrate the Cult of Eris and steal back her mother's soul. But her only way in is through her devious half-brother Finch, the same guy who was Katherine's most devoted bootlicker not too long ago.

Joining a cult counts as sibling bonding time, right?

Left with no choice but to break Finch out of prison, Harley must play the part of a loyal cultist. Within Katherine's inner circle, deadly initiation trials and watchful enemies make every moment a battle for survival.

Harley hasn't forgotten that Finch once belonged to the cult himself, and she wonders if she'll end up with a valuable new ally ... or a knife in the back.