A young girl comes across an injured dog in a park but doesn't tell anyone what the battered scrap of paper attached to its collar says: "Help us." Oliver Anchor-Ferrers is recovering from heart surgery at his grand country home when his wife discovers something horrifying in the garden, a grisly sight all too reminiscent of the tragedy that traumatized the family 15 years ago and haunts them still. It's impossible: how could they have let that man out of prison?