We all have dreams we want to achieve and we will do everything in order to realize those dreams. But sometimes, achieving those dreams require going through extreme measures, and to Mathew Harris, he really didn't mind going through those measures at first, but as he went after his dream, concocting elaborate lies to cover up past elaborate lies, he didn't realize that he is slowly morphing into a person or a monster that nobody would've thought he'd become.
Mathew was just really in the wrong place at the wrong time. He was just a simple porter working in a busy hospital in London, trying to make something of himself, despite having previously dropped out from studying biology. He just wanted a better life, until ideas started blooming in his head. After witnessing a car accident, where the driver was instantly killed, and learning that the man, named Simon Hennessey, was a doctor at the hospital where he works, and had been applying for a residency at another hospital in Bristol, Mathew decides to fill out a job application, and applies for the job himself under the late doctor's identity. He gets accepted and before he leaves, he explains to his friend, Moran that he has decided to travel abroad. He settles in Bristol where he, as Dr. Simon Hennessey, is assigned to a busy Accident & Emergency (A&E) department. There he meets Taylor, a nurse who becomes smitten with him, they soon have an affair. After saving a patient's life, Mathew becomes increasingly arrogant and conceited and started to want more. His arrogance eventually leads for one of his patients to die under his care, which Taylor takes the blame for. Mathew meets Moran, who's decided to become nurse, again, and Moran takes his confession badly. Not wanting for his secret to get out, Mathew kills Moran. Soon, Taylor finally figures out Mathew's secret. She confronts him, however he convinces her into identifying Moran as Mathew Harris, so he can be legally declared dead and continue his impersonation of Dr. Hennessey. Taylor does so, setting Mathew free of any crime.
Because of the situation, Mathew decides to transfer to another hospital in nearby Salisbury. He has however also agreed to stop pretending to be a doctor and move to London with Taylor. But he deceives her and leaves her in London for his new job in Salisbury.