Will could never have predicted how much his life would change when he is knocked from his bicycle by a hit-and-run driver whilst returning home from his London clinic. His wife, Lara, takes him to an A&E where he is diagnosed with concussion. Having cancelled his clients’ upcoming appointments, he spends the following week in fitful sleep. When Will returns to his practice, something is very weird and very wrong. It seems that Will – or a form of Will – held the appointments with his regular clients whilst he was at home asleep. This Will gave some shocking therapy that was completely out of character for him – and he finds himself bringing up things in their history of which they have no memory. The sessions go badly, and walking home, Will passes the London Eye. A young woman in a gondola smiles at him and takes his picture. She wears a red sweater and white jeans. When Will goes to a restaurant, the same woman appears at the next table. Later, she appears at his studio, having made an appointment. She wants Will to be her therapist. Chance encounters with her become more frequent and more bizarre. What’s more, as they start to take a toll on Will’s marriage, his livelihood and his sense of self, it seems Emma knows a lot more about Will than she should.