"Lie to Me" is the 979th episode of Casualty and the 18th episode of the 30th series. It was preceded by "A Life Less Ordinary" and followed by "Black Alert". The episode was directed by Jamie Annett and written by Kim Millar. It shares its name with a series 21 episode which aired in 2007. Coincidentally, both are Dixie centric.
Behind the scenes content of the episode's filming showed that the fire scene was filmed by the actors wearing protective clothing, and thus it was probably filmed using real fire. This episode also marks the end of the storyline involving Dixie and Jess, after it started in November of the previous year. There was a continuity error in this episode, when Nikki slams the door, it appears to be open again from a shot later on.
A row is sparked on Olivia's birthday when Jess buys her a smartphone that her and Nikki has agreed not to buy. Whilst cutting peppers, Nikki accidentally cuts her finger, and angrily pushes Jess back into a glass cabinet, and she gets a shard of glass embedded in her back. Olivia runs into the bathroom and calls for an ambulance. Iain and Dixie arrive in response to the call, and take the three of them into the ED.
Back at the ED, Charlie tells Cal that he has to tell Ethan about what he discovered about their birth mother, as it's unfair to keep it from him. Later in the day, Cal treats a pregnant lady, Cheryl, who isn't telling her husband, Dave, about the fact she's got cancer, as she doesn't want to worry him and plans to have the chemotherapy after she's given birth. Despite the fact she thinks she's protecting him, Cal sees it as an act of selfishness. Meanwhile, Jack is busy organising a fundraiser at The Hope & Anchor. After Robyn's initial ideas prove to be rubbish in his eyes, he decides to have a date with Lofty as one of the top auctioning items, to which Lofty has a hard time saying no.
After Jess, Nikki and Olivia get to the ED, Rita tells Ethan to keep Nikki in as long as possible whilst she tries to organise a visit from the police and a social worker after Dixie raises suspicions. Whilst Jess is being treated, Olivia wets herself and Dixie takes her to get changed. Whilst in the toilets, Dixie convinces Olivia to tell Jess about her wrist injury, and that Nikki caused it weeks ago. When she tells her, Jess promises that Nikki won't be seeing them anymore and they leave to go to their home with Dixie. Meanwhile, Nikki's treatment has ended, but when she goes to find Jess she sees that they've left already. She asks Big Mac where they are, but he says that they have been discharged already, which prompts her to go after them. Elsewhere, Cal convinces Cheryl to tell her husband about her cancer, but even so she convinces him it will all be alright. Also, Dylan tries to convince Lofty to face up to Jack and tell him he doesn't want a makeover for the auction, but Lofty tries to explain how hard it is to say no to him.
When Jess arrives back at her house with Dixie and Olivia, they begin searching the house for her new phone, but Nikki managed to beat them there and grabs Olivia when she's on her way to the living room where Jess and Dixie are. Nikki says that they can be happy, and that Olivia should make a wish and lights the birthday cake. After Nikki lights the sparkler on the cake, Olivia wishes that she would go away which angers Nikki. She picks up the lit cake and hurls it towards Olivia and Jess, calling them ungrateful. The sparkler quickly starts a fire by some nearby objects. However, just before the fire starts Dixie finds the chance to phone for help.
Dixie manages to get Jess and Olivia out of the house, at which point Iain had just arrived in an ambulance. Dixie then goes back into the house with a fire extinguisher and finds Nikki trying to put out the fire with a blanket. Dixie tells her that they have to leave, but Nikki says no and carries on in her efforts. However, a flaming curtain falls on Nikki when she accidentally falls backwards. Dixie manages to save Nikki from the fire, and they all go back to the ED. Meanwhile, Charlie brings up the subject of genetic testing, but Cal is still in denial. He realises he needs to tell Ethan what he's discovered, but when he witnesses Ethan's own mental crisis, he thinks he would only be making things worse. Elsewhere in the ED, Jack starts to prepare Lofty for the auction by waxing his chest, only for Robyn and Louise to walk in after hearing him in the on call room. However, things only get worse for Lofty, as Rita walks in whilst Jack is spray-tanning his bum, leaving her questioning his eligibility for a promotion after all.
Cheryl is on her way up for her x-ray, but goes into labour, and they realise a caesarean section must be done. Connie helps to deliver the baby, and even though Cheryl's life hangs on the line, she pulls through. Meanwhile, Jess goes to visit Nikki, who has suffered major burns to her hands and face, and will face scarring. Jess says she'll have to end it, and when Nikki asks if she forgives her, she says yes for her, but she could never forgive her for what she did to Olivia. After making her statement, Jess meets Dixie in reception and tells her that the police are putting her in a safe house for the time being. They hug, and Dixie realises that Jess may have feelings for her, but they are interrupted by Olivia, who Dixie convinces will be okay.
After their shift, Jack, Louise and Robyn arrive at The Hope & Anchor, but Jacob arrives and tells them that Lofty is tied up with work and won't be able to make it, but says Lofty's asked him to stand in for him. When the auctioning starts, a group of girls appear to be taking the lead in the auction, but Jack suddenly steps in by offering £200, and wins the date with Jacob. Shortly after, Dixie and Iain arrive at pub and Dixie is applauded for her heroic work, but she says she's not in the mood for it.