Iona Griffri returns home one evening to find her family murdered and her father, Eurov, missing. Her family home is entirely submerged in water, and a strange, unnamed girl lies dead in her bed. As the police declare her father the main suspect, Iona is forced to confront how much she really knew about the man who raised her. Could he have been capable of such a crime? And who is the mysterious girl left behind? With the help of the morgue attendant looking after her family's bodies, Iona goes on a journey to uncover the truth behind those final weeks of her family's life. Hidden in the fragments of her father's final manuscript, recovered from the flood, an unimaginable secret slowly rises to the surface. A terrible sin finally revealed.