Deception and secrecy
The plot of the novel revolves around a secret that Laurel knows but no one else does, and it ends with a secret that Jimmy knows but she does not. Laurel's question of her mother's erratic behavior and murder of that man long ago still lingers, but it's not even the worse part of her problems. Her mother may be an identity thief who also murdered Dorothy.
Insanity
Both Dorothy and Vivien are quite possibly insane, driven crazy by the unimaginable paranoia and shell-shock of having lost one's family in a random bombing. The PTSD alone from the blast would be bad enough without the addition element of loss. No doubt, the characters in this novel are being pushed to their limits of their sanity, and then they're pushed further.
The trauma of war
War is traumatic for soldiers, sure, but perhaps nothing is more traumatic than for innocent civilians to be attacked in their own homes by bombs. Dorothy and Vivien's lives are deeply shaped by war, by death, and ultimately the two women share a traumatic journey because of it.
