The autumn of 1952. George VI has died, and England waits to welcome its new monarch. Meanwhile, worlds away, John Standing teaches Greek in a shabby prep school. Or at least he did until yesterday. With his department unceremoniously done away with, John decides to visit the continent in search of culture, adventure...anything to get him away from the crushing monotony of his life.
It is said that everybody has a doppelgänger, somewhere in the world. Held up changing trains, John goes to a bar. It is there that he spots Johnny Spence and feels a bolt of electricity. Johnny is his mirror image - the likeness is uncanny. They drink into the night, discussing their problems, transfixed by their similarity.
John is in search of human connection, Johnny craves an escape from his responsibilities – he is an aristocratic landowner, reluctantly heading home after a disastrous business venture. The two men spend the night in the same hotel. But when John awakes the next morning, Johnny is nowhere to be seen – and a driver wants to take John “home”. Some deep impulse responds to the crack of opportunity, and John literally steps into his double’s shoes.
Arriving at the crumbling stately home, John discovers a house swarming with people. Johnny is in possession of a beautiful young wife and an eerily precocious daughter, a brother and sister seething with resentment and a mistress who happens to be his sister- in-law. Finally, John meets Lady Spence – Johnny’s opium addicted mother, who broods over the house from her upstairs bedroom.
So pure is the resemblance Johnny’s family are instantly taken in by his substitute. John negotiates the initial hurdles clumsily, but without giving himself away. Thereafter, he begins to understand the various crises facing the family. Johnny’s fecklessness has allowed them to slip into financial ruin. The glass foundry attached to the house has suffered decades of mismanagement. Most perniciously, his casual cruelty has suffocated everyone around him. John goes about setting things right. As he restores order, he finds himself becoming intoxicated by the meaning and purpose that he has done without for so long. Johnny’s overflowing life includes a number of beautiful women – and soon John is falling into bed with mistress Bela and falling in love with his wife Frances. With every day that goes by, John is wound tighter into the other man’s life.
Just as it seems there is no going back, Johnny returns and sees his 'scapegoat' is rising to the challenge rather than taking the blame as he had planned. The story takes a lethal turn as Johnny uses his perfect alibi to attempt to murder his wife – and claim her substantial marriage settlement.
In the climax, John tracks down his twin to the foundry – and the two men fight desperately for the one life at stake. Our hero emerges triumphant before incinerating Johnny's body in the hot ovens.
John returns to discover that Frances will survive, and the house, family and all the trappings of Johnny’s life are his for the taking. The story ends with a glimpse of the family six months later. Everyone is gathering round to watch the new Queen’s coronation, with Frances visibly pregnant.
We end on John – the king is dead, long live the king.