A strong marriage can cope with the unexpected. But can it survive the unimaginable? American nanny Eleanor was never meant to meet Alex. But when she walks into his London police station to report a stalker, everything changes for them both. He's convinced he can protect her from anything and anyone. She hopes her darkest days are behind her. As they settle into their life together, two hundred miles away another young couple faces an uncertain future. Christie knows Paul is a decent man, but she can't shake a clairvoyant's warning: 'Never trust your husband . . .' When a work trip tests their bond, will she overcome her fears for the sake of her family? Ten years later, both couples are still together, for better or worse. But as doubts and resentments begin bubbling steadily to the surface, all four of them start to question the choices they've made. At least the secrets they all brought into their marriages are still well hidden. For now.