Helena has always been a little different from everyone else, but over the years, she's learned to hide that she doesn't always understand social niceties. She has a loving husband and daughters and a business, and life is going smoothly, until she hears that an inmate has killed two guards and escaped from the local prison.

The authorities believe they are on his tail, but she knows the truth. He has disappeared into the marsh, and he's coming for her. The man is her father, and until she was a teenager, she didn't know that he had kidnapped and held captive her mother. Faced with hunting down a man she all-at-once fears, loathes, and loves, Helena goes into the marsh.

The Marsh King's Daughter is a slow-burn of a novel--a little slower than I would have liked, but still unsettling in all the ways a psychological thriller should be. There are thrilling moments that justify the genre designation, but the story is told largely through flashbacks to a childhood tinged with a new interpretation following Helena's discovery of their captivity. It's a unique twist on a psychological thriller, as the reader is forced to understand her love for her father while knowing him to be a monster.