A girl of eleven is returned seven years after being abducted, with no memory of herself. DNA tests prove conclusively that she is Claire Halward but her father, Nick, knows she is not. There is only one person who knows who she really is: her abductor.
Her mother, Karin, was destroyed when her daughter went missing. No amount of therapy, antidepressants or affairs have helped to alleviate her loss. She struggles to integrate Claire back into old life. Claire remembers nothing. Empty and silent, she has violent dreams of a twin sister she doesn’t have. For the extensive scarring on her body, there is no explanation.
Nick is disconnected from the family, disappearing into his job every day in the City. He is watched by a man with silver-blue eyes, a man who knows Nick’s secret. He is still watching when a psychiatrist friend agrees to help Claire recover her memory. But Claire regresses to a different abduction scene and sees the man with the silver-blue eyes, her abductor. When they first meet and talk, briefly and desperately, he tells her that her name is Chloe.
Despite every effort, social and educational, with Claire in therapy, the family slowly disintegrates. Karin can’t reach Claire. Nick is aware that Claire knows she is not Claire. Unable to tolerate her own despair, Claire cuts herself and soon after runs away to find her abductor, to find out the truth about herself.
John Fox works as a night porter at UCH. He doesn’t sleep but lives in darkness. Returning from holiday, he discovers Claire has been staying in his Kings Cross hotel room. On that same day, Claire has arranged to meet Nick in the City but doesn’t show up after she sees John Fox’s twin. A misunderstanding leads her to sleep rough for three weeks. John, Nick and Karin, in their separate worlds, are all frantic to find her.
Finally she returns to John and he is forced to tell her the truth. Abducted as child himself, he was retained and worked for an alien operation using genetically identical non-birth twins to generate a pre-annihilation force that opened a layer of space called Ultra. The battle to free himself as a drone began after he witnessed the death of the real Claire.
John’s explanation does not include the whereabouts of her actual parents. Many of his truths remain unpalatable. Still Claire wishes to live with him. When he sees the harrowing evidence of her acts of self-harm, he shows her the deep scars of his own suicide attempt, but he does not tell her that it was done in an effort to return to Ultra.
Against her will, Claire returns home. Nick is alone. Karin has left him. Nick picks a fight which John wins. But Nick can’t report John. They both know too much. After an attempt at a family reconciliation, Nick confesses to Claire that a year after her abduction, she had been returned and he had inadvertently killed her.
Four years later and Claire no longer believes Nick’s confession. Nor does she believe John Fox’s version of the truth. When she finds him again, it is to consummate a passion that neither can resist. He tries to prove to her the aliens did exist by showing her the device that controlled him on the ship. If she does not believe him, then she has to accept that he is a paedophile, an option that has to be worse because she is in love with him. He destroys the device. His protection from the aliens – whom he has never seen – is lost. But in the end, he cannot prove to her that they are on a twin planet, another identical Earth.
At dawn a second moon sets on the horizon.