Needful Magic is the eighth book in the Magic story arc in The Merged Worlds series of fantasy books. Stacey Bowen, Vampire and Daggerwoman, in disguise as Marion Blackwood, member of the Baltimore Vampire Council, along with her companion, Angela Mack, Daggerwoman, disguised as Wren, attend a regular meeting of the Baltimore Vampire Council. Marion is meant to warn members of the Vampire community of the impending War. This war is meant to rip aside the Law that has held the relative peace between the Earth, the Hidden, Hell and Heavenly realms. The war is meant to rip that law aside. The Vampire Council will stand for the Law. Even as Marion/Stacey is speaking the meeting is disrupted by an attack. Wren must protect her vampire.
As preparations for the war continue, the Daggers are warned of a building army of vampires. In order to forestall these creatures from entering the war, they plan to deal with it. As they do, they find a former enemy has resurfaced, watching them from the shadows. Secrets are exposed and new allies are found. Angie/Wren makes a new friend, or is he more than a friend? The Daggers go into action.
