Nicola and her husband Howard have decided not to have children but when their twin nephews are orphaned in a car accident they have no choice but to offer the boys a home. After being brought up in Egypt, their father's country, the twins are spoiled and autocratic. They also have the unnerving habits of being able to finish each other's sentences and answering to each other's name .. almost as if they are not two children at all but different aspects of the same one. As a child psychologist, Nicola is prepared to allow them some leeway while they adjust to their new surroundings and guardians - but she has reckoned without the boys' ability to tune into the thoughts of the adults around them and to play on their doubts and fears, with horrific results.