The Tiger in the Well by Philip Pullman
Sally is 25, and somebody wants to destroy her. She receives divorce papers from a man she has never met, let alone married - yet this trap is so well laid that she is powerless to prove otherwise. When custody of her precious daughter is awarded to this evil stranger, it is the beginning of a terrifying struggle in which Sally will have to fight, with a gun if necessary, for the freedom of her family. The third instalment of the quartet.