When Rowan awakens to find her body no longer her own, she discovers she has been imprisoned within her own mind, her flesh commandeered by the ancient entity known only as The Borrower. Unlike its past victims, Rowan has not been erased - she has been kept, a captive audience to the creature's restless loneliness. Forced into a nightmare companionship, she learns fragments of its dark history, its true enemy lurking in the woods, and the cult ties binding her own family to its survival. As Rowan pushes back against her captor, battles erupt both in the world beyond and in the psychic void between them, blurring the line between resistance and union. In the end, she must decide whether to destroy the Borrower, surrender to it, or accept a terrifying fusion that leaves neither truly human.