Lucy at War: An Undraland Blood Novel

Lucy at War is book seven in the nine-part Undraland series, which is based in Scandinavian folklore.

After Tucker's betrayal, Lucy finds herself underground, imprisoned by the surviving Sirens. She clings to Jamie in her mind as she endures mental and physical torture when they try to break her spirit, and her laplanding bond to Jamie.
Lucy must hold tight to herself, deciphering with care between the voices in her head and the ones around her. When a message comes to her from one of the voices in her head, she knows she must go back to Undraland.