"All in a Day's Nightmare - Part One" is the 818th episode of Casualty and the 37th episode of the 26th series. It was preceded by "Teenage Dreams" and followed by "All in a Day's Nightmare - Part Two". The episode was directed by Jon Sen and written by Tony McHale.
Father-of-two Clive is brought into the ED with serious injuries, but he lies to his family about how he received them. The mystery deepens when a strange woman claiming to be Clive's wife arrives at his bedside. Despite the presence of bickering police officers Chris and Preeya, it's left to the more experienced Charlie to work out that Clive is being harassed by loan sharks. Meanwhile, Linda is forced to bring a suspended Britney into work with her, but the teenager defies Linda's ban on using the ED wifi and wheedles the password out of Lenny. When Lenny discovers that she has arranged to meet someone she's been talking to in a chatroom, he chases her out of the ED. Panicked, Britney gets in a car with the stranger. Elsewhere, Scarlett's first meeting with Lloyd's family doesn't go according to plan when she turns down his mum's specially prepared dinner.