Hester and Harriet are reluctantly driving to visit relatives on Christmas Day when they come across a young woman hiding with her baby in a bus shelter. Seeing the perfect excuse for returning to their own warm hearth, the sisters insist on bringing Daria and Milo home with them. But the arrival of a sinister stranger looking for a girl with a baby, Hester and Harriet's carefully crafted peace and quiet quickly begins to fall apart...