"Where the Truth Lies" is the 1002nd episode of Casualty and the 41st episode of the 30th series. It was preceded by "What Lies Beneath" and followed by "The Fear". The episode was directed by David Innes Edwards and written by Henrietta Hardy and Jeff Povey.
At their house, Brian is smoking upstairs when he hears Hazel enter the house with Rihanna. In a panic, he goes to throw the cigarette out of the window but it ends up bouncing back in and starting a small fire on the carpet. He manages to seemingly extinguish it with his foot, despite sustaining a bad burn to the sole of his foot. He later goes out shopping, but whilst he's out the fire reignites and quickly spreads. Hazel is soon woken to find the upstairs filling with smoke, and is able to get outside the window on a ledge with Rihanna. The paramedics are called, and shortly after a large explosion causes Hazel to drop Rihanna but Jez manages to save her.
Back at the ED, Charlie realises that Connie and Jacob are back together although she asks him to keep it quiet for Grace's sake. Shortly after, Charlie informs Connie about the house fire involving Dylan's family and decide to tell him. When they're admitted, Dylan takes control and notices that Brian is limping, although he tells him that it's just a blister. Back in reception, Noel, Louise and Iain discuss Rita's lies and that she's called in sick for the day.
Meanwhile, jaded film star Vera Vintner is admitted to the ED with a suspected sprained ankle. She's treated by Cal, Robyn and David and David is starstruck as he recognises Vera from one of his favourite films. Vera's accompanied by her sister Caroline who insists that she needs to let the doctors treat her instead of worrying about her fans. Cal examines her ankle and finds that it's not broken and Vera asks Caroline to read messages from her fans, although when she becomes angry when Caroline walks off Cal discovers an infection on Vera's ear caused by a large earring.
David notices Glen sitting in the ED and assumes that he's reliving his wife's final moments. However, he asks Noel to find the doctor who treated his wife on the system but he's unable to find anyone. Dylan continues to treat Hazel and Rihanna, and they're both in stable conditions. However, Max sees Brian outside the ED tending to his foot injury and notifies Dylan. Upon looking at it, Dylan realises that it's a burn and Brian's forced to admit the truth about how the fire started.
David takes a look at Glen's social media and finds no pictures or evidence of his wife which back up his suspicions that Glen may be lying about having a wife at all. Meanwhile Cal continues Vera's treatment and he's able to drain the abscess on her ear caused by the infection. Robyn speaks with Caroline and starts to have suspicions and Caroline eventually admits that Vera has no fans at all and she makes up the messages to boost her spirits. David later confronts her about it and tells her it's unfair although he comes to understand how the truth can sometimes hurt people but it's the best thing to do. This prompts him to call Robyn and Glen into the staff room and he confronts Glen about his suspicions that his wife doesn't exist. He eventually admits the truth and Robyn shouts at him to leave.
Brian tells Dylan that he's going to leave Holby as a result of the realisation that he can't change and that he's simply no use to Hazel and Rihanna. Dylan goes to visit Hazel and Rihanna and she informs him that Brian called her to tell her that he's leaving. She asks for his support to care for Rihanna and he agrees to take her for a couple of days a week. As a nurse takes Hazel to the relatives room, Dylan sings Rihanna to sleep.