The penultimate episode in this nail-biting BBC medical drama which stars upcoming Doctor Who Jodie Whitaker as a nurse who decides to pretend to be a doctor in a Scottish hospital - what can go wrong? Plenty, as you have probably already seen. Tonight's episode sees Andy with a decision to make after his discovery while Cath/Ally is faced with saying goodbye to her dying father in Sheffield. Her drama doesn't end there though as when she returns to work, a fatal error leaves her facing a stark choice between protecting her identity or falling further into the lie.