"Binge Britain" is the 1027th episode of Casualty and the 23rd episode of the 31st series. It was preceded by "You Are Your Only Limit" and followed by "Slipping Under". The episode was directed by Paul Riordan and written by Laura Poliakoff.
Iain's sister Gemma fails to show up when she's supposed to be meeting him at the youth centre which leaves him disappointed. The following day, Gemma returns home to her mother's flat to find that the TV is missing along with some of their posessions. Just as she's about to leave with a necklace, her mother Kim returns. However, she warns Gem that some men are after her after she failed to pay them back money she spend on alcohol. They corner the two on the stairs and in the confrontation, Kim falls almost two-storeys down the gap in the stairs. In a panic, Gemma calls for an ambulance as the men make a run for it.
Charlie and Duffy return from their honeymoon from Tenerife, having missed their plane and having to go straight into work. However, some of the team are unimpressed with their timing on a busy Saturday night. David also tries to persuade them to give Robyn some advice with her pregnancy.
Meanwhile, a local Robin Hood themed hen party takes a turn for the worse when the maid of honour Karla accidentally shoots Daisy, the bride-to-be, in the arm with an arrow. She's admitted to the ED, and it's not long before her fiancée Greg shows up upon hearing the news. However, it's clear that Karla is uncomfortable with the way he's treating her. After music starts playing, things soon start to spiral out of control in reception with an influx of drinkers. Elsewhere, Connie and Sam remain at Grace's bedside when she wakes up. Sam is offered the new post of Medical Director at the hospital, whilst Connie is more focused on Grace's recovery.
Iain arrives at the scene shocked to find Gem and his mother. She's brought back to the ED and Lily makes a shocking diagnosis that Kim has cirrhosis of the liver. Despite her warnings that she may die if she carries on drinking, Iain catches her with a can of cider in cubicles. Gemma makes a run for it whilst Iain's back is turned, but he's having concerns of his own when Kim is rushed into resus. They're able to stabilise her and Iain goes looking for Gem. Elsewhere in the ED, Connie suspects that Grace's inability to talk is psychological and not a physical condition.
Karla voices her concerns about Greg's disloyalty, but Daisy dismisses her claims. Karla is also found to have got food poisoning from the food she ate earlier. However, Daisy later discovers Greg trying to get it on with Karla in cubicles and tells him to leave, not wanting to see him ever again. Daisy apologises to Karla, but she reveals that they've grown apart and aren't really friends anymore. Dylan expresses concerns about the number of binge drinkers being admitted to the ED, and comes up with the idea to implement a booze bus that goes around the streets to prevent drunk patients being admitted. Alicia asks Ethan to go out for a drink, but he declines, eventually revealing that Cal's been in a bad way following their break-up.
Gemma returns to her mother's flat, but is shocked when the men turn up once again. She calls Iain for help, and he and Jez turn up to save her. They have a violent confrontation, but eventually they come to a resolution and the men leave. Gemma returns with Iain back to the ED where their mother had awoken. Pessimistic about her own recovery from her alcoholism, Kim admits defeat which angers Gemma even more. Iain reveals to them that he agreed to pay off her debts to the men, and later offers Gemma a place to stay at his.