August 16, 2137: The Maiden of the Waves ferry boat makes its third ever voyage, heading from Florida Harbor and to Fowey Port, in Cornwall. The Arscythe family - Roma, Andrea, Reuben, and Madeleine - enjoy luxury on the ferry as they travel back home from their vacation spot in Florida Territory.
August 18, 2137: The Maiden of the Waves is the first ferry boat to be set on fire from the inside and burn above the waves. The fire is ruled to be an accident. There are forty-six survivors out of nine hundred on board, and as far as anyone is concerned, Madeleine Arscythe is not one of them.
Hidden deep beneath the waves about thirty miles north of Cuba lies a secret- one that has been kept safe from humans for as long as it has existed, with the odd exception.
When the Maiden of the Waves sinks, Madeleine Arscythe becomes one such exception.
In the epic conclusion to the Devil's Deal series, Freya has one final chance to discover the full potential of her own power, and to use it to restore balance in the universe - once and for all. After the destruction caused by Roisin, Ferya and Torix come to terms with their losses and mistakes... And prepare for a final battle that will change everything.