When eighteen-year-old Helena is sent to be a governess at Archfall Manor - a beautiful but crumbling manor house, perched at the edge of a causeway in the North Sea - she feels confident she will know how to deal with the esteemed but eccentric Cauldwell family who own it. But it quickly becomes clear that the Cauldwells are hiding more than Helena could ever have dreamed of.
A series of sinister events come to a head with a gruesome death - swiftly followed by another. Worse still, with the path back to the mainland cut off by a terrible storm, and no way to get help, suspicions and paranoia quickly run rampant.
But the Cauldwells aren't the only ones keeping secrets. Helena has some very important ones of her own - and soon she begins to wonder whether dark powers beyond her control might be forcing her to twist the fate of the family - and her own destiny - forever.