Cath Hardacre is a hardworking and skilled nurse who loses her job for whistle-blowing and is forced to take drastic measures to provide for her daughter. Out of desperation, Cath seizes the opportunity to steal her best friend's identity as a senior doctor and start a new life in Edinburgh. Burying herself deeper and deeper in the imposter persona, she realises she could get everything she ever wanted - but with her old life threatening to destroy her fragile creation, how far will she go to protect it?