Shadow Souls by L. J. Smith

Elena, Bonnie, and Meredith join forces with Damon to venture into the Dark Dimension to rescue Stefan from a brutal prison. Posing as nobles and slaves within a city where vampires reign and humans are property, they search for the keys needed to free him, forging uneasy alliances and navigating treacherous courts. As Elena’s powers evolve and her connection with Damon deepens, desire, betrayal, and sacrifice test the group’s bonds, culminating in a daring rescue and a devastating cliffhanger.

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