At the Wyvern Ambulance Service Communications Centre, Iain starts his first shift as a call handler. He answers a call from a police officer named Rox who has found three men lying unresponsive at Milford Warehouse. She begins to panic, but he tells her to calm down and check to see if the men are breathing or are experiencing any blood loss.
Rox soon tells Iain that she has found illegal drugs, and one of the men has tied condoms together to form a tourniquet, leading Iain to believe that they have overdosed. He talks her through performing chest compressions, and one of the men starts to come around. Iain instructs Rox to go to the fridge to retrieve the naloxone kit. She administers an injection, but it has no effect. She starts coughing and complains of a headache, and, as Iain tries to confirm her location, she mentions that one of the men's lips are red. Iain realises that they are suffering from carbon monoxide poisoning, and he orders Rox to get out of the building, but the call ends. Laura tells him to keep calling her, and Iain manages to re-establish a connection.
Rox manages to escape the warehouse, but she accidentally runs into the path of the first responder and causes him to crash his motorcycle. She rushes to help him, and she is horrified to find that he has suffered an open fracture. She puts pressure on the wound as the ambulances arrive. Laura implores Iain to take a break. In the staff room, Iain tells her that it "kills [him] not being there", but she assures him that the experience will help him get back to working as a paramedic. She warns him to be careful and reminds him of the set questions that he is required to ask. He suggests that the team are being nice to him because of his suicide attempt and insists that he is okay.
Iain attends a session with his therapist Claire Wakelins who believes that he is showing some signs of improvement, but he claims that it is just his medication kicking in. She tells him that only he can cure himself. Iain decides to leave, stating that he is only there so he can get back to work, but she asks him to stay. He begins to recount a story he saw on the internet about a man who survived a suicide attempt and started preaching about his appreciation of life, and Iain claims that he does not want his life back most of the time as he believes that his pain has gone on for too long. Claire reminds him that that is is the reason why they are speaking, and she asserts that his problems stem from his childhood and not just from Mia and Sam's deaths. Claire posits that trying to take his own life was not an answer but a question that needs answering in order for his life to have meaning again. She asks him if he has found himself a pebble, and he shows it to her and explains that it came from Mia's favourite beach. Claire tells him to come back when he is ready. At home, Gem has prepared Iain dinner. He thanks her for trying so hard for him, but he explains that he feels nothing. After she takes his plate away, he goes outside to beat his punching bag, but he ends up hurting himself due to his recent surgery.
On another day, at the communications centre, Iain receives a call from a young girl named Frankie who is trapped in a house fire with her father and sister. She tells him that her father is groaning in pain, and she needs to save her sister Storm who is in the kitchen. However, Iain instructs her to close the door, and he is relieved to hear Storm sobbing in the background. Frankie tells Iain that her father has been drinking, and, when he suggests helping him, she asserts that he would not like it. He asks her if her father has a mobile phone, and she tells him that she has one. Iain decides to start a video call with Frankie, and he is disturbed by the state of her face. He talks her through putting her father in the recovery position. The father begins to cough as the fire begins to enter the room. Iain orders Frankie to take Storm to the window, and the call ends. Laura tells him to write up a formal report if he has any concerns about the welfare of the children.
On his way home, Iain stops by a toy shop and buys a toy unicorn for Frankie. He arrives at his house as Gem is leaving to go to work, and he asks her to give Frankie the toy and tell Connie about her history of abuse. Gem says that it is good that he cares about Frankie and Storm's plight, but he insists that it is not that simple. Later that night, Iain parks on Claire's road and calls her. They start a session, and Iain discusses Frankie's case. He tells her that her situation reminds him of his childhood and his relationship with his mother. Claire explains that children develop their sense of self, and, as a result of his upbringing, he mistakes admiration for love and lacks self-love. Iain dismisses her psychoanalysis and questions her decision to start drinking wine at three o'clock in the morning, but, she claims that, as a former paediatrician, she knows exactly how the pain hits. She explains that, as he made sure that his job was everything, he was destroyed when it all went wrong. She posits that the frightened face he saw on the video call was him and encouraged him to own that fact.
At work, Iain tells Katie that he cannot attend her engagement party, but she tells him that it has been postponed as her boyfriend Jay was not well. At his desk, he receives a call from a woman named Jodie whose partner Lou is giving birth on a motorway. He talks them through delivering the baby, and Lou gives birth to a girl who they decide to call Iain, but Lou suddenly starts giving birth to another child. Jodie manages to help deliver the baby when it becomes stuck, resulting in the birth of a baby boy. However, the baby is not crying, and Iain waits in suspense as Jodie tries to resuscitate it. To Iain's delight, she successfully gets the baby to start breathing, and they decide to name the boy after him as well. Once he finishes the call, Iain receives an ovation from his colleagues.
In the staff room, Laura gives Iain a badge for his first child delivery call, and Iain asks her if Katie is alright. She explains that Jay had come off his bike a couple of weeks prior. Meanwhile, she informs him that the three men with carbon monoxide poisoning survived, and she praises him for his work with Rox.
That night, in his car, Iain tearfully tells Claire that he felt normal for the first time in ages, but now the emptiness is hitting him. She urges him to hold onto the feeling of relief and to remember how it is possible to feel better again. When she tells him to see her again, he claims that he is all right, but she reminds him that coping is not the same. At 3 am, Gem walks into Iain's room to turn off his radio, but she begins to panic and tells him to wake up. He tells her that the pressure of her constantly checking up on him is too much, but she asks him if he has once thought about how she feels. He apologises and tells her that the recent calls have helped him feel things again and claims that it scares him. He asks Gem about Frankie, and she tells him that she wants to see him. Gem tells him that she is there for him, no matter how long it takes for him to recover.
At the communications centre, Katie desperately pleads with a suicidal caller to speak to her. Iain notices and asks Laura to let him take over. She initially refuses, given the situation, but she eventually allows him to take the call. He promises the caller that he understands what they are going through and encourages them to listen to him. He explains to them why they have been pushed to suicide. The caller tells him that nobody cares about them and refuses to give him their name, calling it and any means of persuasion "meaningless". Iain recognises the caller as Rox and tells her that she saved the men's lives, but she denies it. She believes that it is too late, but he assures her that he knows how she is feeling. She asks him how he could possibly understand, and he reveals to her that he had also tried to take his own life. She queries if he was happy to be found, and he tells her that he does not know yet.
Iain asks Rox to get back to safety, but she asserts that there is no going back. However, he reminds her that they both know that there is always the day after. He understands that she is planning on taking her own life to make the people who have wronged her understand her pain, but he points out that, while she believes that nothing matters, she has worked hard over the past few years, meaning that something has changed. He promises her that it can change and urges her to give herself a chance and lets the paramedics help her.
As the paramedics arrive, Rox loses her footing and drops the phone into the river below. When the live stream ends, Iain becomes agitated, fearing that his progress in getting through to her has been undone. Nevertheless, Rox accepts another phone, and Iain begs her to let him help her, but she insists that she cannot. He asks her to tell him what has happened, and she explains that she should have passed on the tip-off as she unintentionally blew a covert surveillance and might be fired. He insists that she pulled it together, but she also mentions the incident with the first responder, and Iain realises that she is referring to Katie's boyfriend Jay. Iain tells her that it is part of their jobs and that it is not her fault. He asks her to tell him what she is wearing; she tells him that she is wearing her police uniform. Iain tells her that she is not her uniform as, when she was in the warehouse, she had no rules and reminds her that she risked her own safety to save the poisoned men. He requests her to save her own life, but she asks what will happen next. As Iain explains to her that her pain will not just go away and that she needs to face it, he begins to cry. He promises to help her find support and pleads her to come off the bridge. Ruby helps her down, and Laura informs a crying Iain that Rox is okay.
Overwhelmed, Iain calls Claire and tells her that he got through to Rox and found the way. She praises him for his work and explains to him that, as soon as he put the phone down, he was back with himself. She assures him that he will get better and urges him to give himself time to heal. Clutching his pebble and sobbing, Iain asks her if he could schedule another appointment with her. Outside the ED, Gem takes Frankie to meet Iain, and Frankie thanks him. He asks her how Storm is, and she tells him that they are both fine, thanks to him, and informs him that they have been given back to their mother. When he asks if she is feeling safe yet, she nods and hugs him. After a short moment, Iain reciprocates. Once Frankie returns to her social worker, Iain and Gem go home.
- Michael Stevenson as Iain Dean
- Rebecca Ryan as Gem Dean
- Maddy Hill as Ruby Spark
- Frances Barber as Claire Wakelins
- Katie West as Rox Adams
- Amanda Hadingue as Laura Whiting
- Rochelle James as Katie Langdon
- Nancy Surridge as Frankie Harper
- Kate O'Flynn as Lou Briggs
- Fiona Skinner as Jodie Harvey