When the Blitz starts in London, Dominic Lancaster, injured out of service at the battle of Narvik, accompanies his 10 year old sister Octavia to the family house on the shores of Ullswater in the Lake District.
Octavia is profoundly deaf but at night she can hear disturbing noises in the house. When questioned by Dominic as to what she can hear, she replies: 'voices'. Two nights later she comes into his bedroom to tell him that the dead children in the house want them to leave.
And then Octavia falls mysteriously ill... during her sickness she tells Dominic he must go to the attic. There, he releases an older, darker evil that threatens the lives of Olivia and himself.