"Sleeping With the Enemy" is the 1033rd episode of Casualty and the 29th episode of the 31st series. It was preceded by "Five Days" and followed by "Child of Mine". The episode was directed by Simon Massey and written by Steve Bailie. It is Alicia's second centric episode since her debut episode in September 2015.
Alicia wakes up in Sam's bed, and things are awkward at work. Sam announces that budget cuts are occurring, and therefore all consultants will have to re-interview for their jobs. Although Alicia acknowledges that her job isn't imminently on the line, she's furious when Sam calls her cheap; he reassures her he only meant in a professional sense. At the end of the day, Sam reveals to her that he slept on the sofa, and that they didn't have sex. Nevertheless, Alicia still feels humiliated, and rejects Ethan when he steps in to comfort her.
A young woman, Evie, has her home invaded by a masked intruder, and when she manages to escape outside is hit by a car being driven by her mother, Susie. At the hospital, Susie realises that the man who broke into Evie's home was the same man she'd been chatting to online, inadvertently using Evie's name. When Susie confronts him, he gets violent and cuts her arm with a knife. Stepping in, Alicia picks up a fire extinguisher and hits him with it, whilst security take him away to the police. Susie and Evie are both safe in resus, but Sam is anxious at the thought of having to speak to the board about the incident.
Iain and Gem's relationship is tested when they spend the day together on the rig and Iain is confronted with his biggest fear: snakes. Although they manage to get a man treated for a snake bite, the trio get more than they bargained for when the snake makes its way onto the ambulance. With some advice from the man, they manage to capture the snake, and Iain is impressed by Gemma's initiative.