From the back of the book:
Embrace the darkness of MIDNIGHT with this supplement for the award-winning campaign world. MIDNIGHT usually puts the players in the role of desperate freedom fighters waging war against overwhelming forces of evil. Hand of Shadow at last gives them the power to become that which their characters have hated and feared for so long...minions of the dark god!
Whether they play devoted legates, barbaric orcs, corrupted channelers, or clever collaborators, this book allows players to turn the usual MIDNIGHT campaign on its head, and to explore whether even the most evil of foes have a chance at redemption.
New backgrounds, racial rules, and roleplaying suggestions for evil PCs.
Prestige classes and advantages that are only available to servants of the Shadow.
Plot hooks and campaign progressions designed specifically for evil parties in MIDNIGHT; will the characters follow the path of evil, turn toward redemption, or choose their own way between the two?