Episode 21 is the 1113th episode of Casualty and the 21st episode of the 33rd series. It was preceded by Episode 20 and followed by Episode 22. The episode was directed by David Innes Edwards and written by Pete Lawson.
At a farm, Iain and Ruby treat a man named Mark whose leg has been ensnared in barbed wire. A pair of bailiffs arrive at the property, and inform Mark and his wife Tilly that they have to repossess the farm. Enraged, Mark removes the barbed wire from his leg and runs to his house. The paramedics, bailiffs and Tilly follow him, and they are horrified when he returns with a loaded gun.
Iain tries to get Mark to put the weapon down, but he fires multiple warning shots and accidentally wounds one of the bailiffs. When he overhears Ruby alerting control, he points the gun at her, but Iain confidently asserts that he has run out of bullets. Mark asks him if he wants to test his theory, and Iain dares him to pull the trigger. Fortunately, Mark cracks under the pressure and gives Iain the gun. As Ruby treats the dying bailiff and calls for backup, Iain checks the gun's magazine and finds one remaining bullet.
In the ED, Iain tells his colleagues that he knew that Mark's gun could only fire eight shots, but Ruby only recalls him firing seven. As Ruby is treated for her shock in cubicles, Jan reprimands Iain for taking an unnecessary risk. Later, he visits Ruby in her cubicle, and she says she finds the job too hard, but he tells her to persevere and gives her a hug.
Iain leaves the ED and goes to visit Base. When he doesn't answer the door, Iain enters through a window and finds Base unresponsive on his sofa. He realises that he has overdosed on heroin and calls for an ambulance, but the operator tells him that there are none currently available. For half an hour, Iain desperately tries to resuscitate him. Exhausted, he is forced to give up. However, he soon spots Ross and prevents him from leaving. Irate, Iain blames him for killing Base and starts attacking him. When Ross punches him in the face, Iain knocks him to the ground, causing him to hit his head on an iron in the process.
Meanwhile, Ernest decides to go to the ED for treatment. Although Louise initially tells him that she is only giving him a small checkup, his symptoms start to concern her, prompting her to run more tests. Ethan suspects that Ernest has a thoracoabdominal aortic aneurysm, and consultant cardiothoracic surgeon Andrew Ackroyd is called down from Darwin to assess his condition. However, given Ernest's homelessness and increased risk of infection, he refuses to operate. In the prayer room, Louise breaks the bad news to Ernest.
With some encouragement from Marty, Louise confronts Andrew and tells him that she has found Ernest a place to stay. When she says that Jac Naylor would have jumped at the first opportunity to perform a high risk procedure, he bites the bullet and agrees to operate on Ernest. She finds him outside the department and tells him the good news, and she lets him stay at her house.