Serena is cooking a meal for Sam at he and Andrew’s house. It’s her day off from work and Sam reluctantly gives her his house keys so that she can go shopping during the day.
Carol asks Joanna if she is going to break her pregnancy news to the father of her baby. Joanna says it was a one night stand and points out that she nor the father are expecting to grow old together. Joanna explains that she hasn’t yet come to terms with being pregnant.
Joanna has to tell one of her patients, Ann, that she has cancer. Ann tells Joanna that she doesn’t want treatment for the cancer as it would effect the time she has with her daughter Sally, who has Downs Syndrome.
Serena visits Sam at the surgery. She gives him his key back and announces that while she was out she took the liberty of getting herself one cut. He tells her he will be late home for his dinner as he and Andrew are meeting up with Maurice Freeman, a local businessman who wants The Beeches to have the medical contract to his firm.
Andrew asks Joanna if she will join he and Sam at the pub to talk with Maurice. Joanna says no as she is against Maurice’s firm driving their lorries through Cardale when they carry dangerous chemicals. Andrew is disappointed and Joanna says she may see them at the pub later after she’s done her house calls.
Kate joins Andrew, Sam and Maurice at the pub. She is also against Maurice’s company driving through Cardale and using the community as a waste ground for it’s chemicals. Kate is not happy when she learns that The Beeches may be contracting themselves to Maurice’s firm. As they can continue to argue the case in The Black Swan, Ann and Sally arrive to have a meal in the pub. When Ann is distracted by an old friend, Sally goes on ahead and makes her way to the entrance of the pub.
As night falls, a lorry carrying toxins travels past the pub. When the drivers mobile rings he loses his concentration and control of the lorry. The lorry rolls over shooting something into Sally’s stomach and leaking chemicals outside The Black Swan.
Andrew, Sam and Mike go outside to see what is happening and are shocked to find the lorry lying adjacent to the pub’s entrance. They take Sally to the pub and tell Ann to stay outside as if she comes closer she will get caught in the spraying toxins. Maurice looks at the driver and says it’s not one of his lorries, he says the driver must be moonlighting. Andrew and Sam agree that the best thing to do is to keep everyone inside the pub and wait for the chemicals to be cleared up, many of the customers run out of the pub covering themselves in flying toxins as they go.
Joanna arrives but Sam tells her to go back to The Beeches and set up an emergency clinic for everyone who has been affected by the toxins. Joanna goes back to The Beeches and tells Carol and Kerri that they will have to set up drips and eye baths as most patients will be suffering from burns. Joanna asks Kerri if she’d mind ferrying people from the pub to The Beeches as she would rather stay at the surgery and take charge. Kerri agrees and makes her way to The Black Swan.
Andrew, Sam, Mike and Maurice lift the injured driver Des into the pub. The police put up barriers and road blocks as Kerri takes the minor injuries back to The Beeches. Sally complains of a stomach ache but as there is no outside wound no-one realises she has had something shot into her stomach.
Joanna is weary of keeping all the doors and windows shut because of the chemicals. Kerri is at a loss working out Joanna’s jumpy behaviour but Carol is aware it’s because she is worried for her unborn babies safety.
Joanna dresses Ann’s minor burns at the Beeches and asks her why she won’t have the treatment for her cancer. Ann says it’s because she wants to see Sally turn 15. Joanna explains that if she were to have the treatment there is a good chance of recovery and then she could watch Sally grow past her teenage years.
At The Beeches, Julie is sure something is wrong with Sally, however when she asks Sam to look at her he says he has already checked Sally over and says she is fine. Liz later notices that Sally is becoming distressed. When Sam takes a look there is a sign of massive internal bleeding – Sally is haemorrhaging inside her body. Sam calls The Beeches so that Anna can speak to Sally to calm her down, and he calls through to Derby County to get some blood sent through.
Kate helps Andrew look Des as his circulation has stopped. Andrew is impressed by Kate’s cool head in the difficult situation.
As Sam takes the bloods from a fire crew he sees all the emergency vehicles drive away from the scene. He and Andrew realise they have given up on trying to clear the toxins and have driven away for their own safety.
Serena calls The Beeches and asks after Sam. Carol explains what has happened and says Sam is trapped in The Black Swan.
Andrew tries to get some information from Maurice on the toxins which have spilled outside the pub. Maurice eventually caves in as Kate and Mike blame him for what has happened. Maurice says that Des is his Brother-in-Law and that the lorry was carrying his load.
The toxicologist arrives at The Beeches and reports her findings to the fire crew. She has identified the type of toxin and knows how to get rid of it. The fire crews head back to the pub to start work on diluting the toxins. Kerri tells Joanna they should join the emergency services at The Black Swan. Joanna says she doesn’t think she needs to be there as she doesn’t want to breath in any fumes. Kerri tells her they’ll be given masks but Joanna is adamant she doesn’t want to go. As Kerri pushes her further Joanna reveals she is pregnant and can’t go because she doesn’t want to harm the baby.
Andrew and Sam take a risk and carry Sally out to the ambulance. She is in urgent need of treatment. Ann heads to The Black Swan to meet them and tells Joanna she will have treatment for her cancer.
The people trapped in the pub are allowed to come outside as the toxins are being cleared away. Andrew tells Maurice he will see that is firm is closed down. Kerri arrives and sees Sam, she hugs him and tells him she was worried about him. Serena arrives and immediately fusses around Sam. He tells her he’s going to the hospital to see Sally and say’s they can do something tomorrow.
At The Beeches Joanna treats Andrews wounds. Andrew says ‘congratulations’. Realising he knows about the baby, Joanna tells him she didn’t tell him herself because she hadn’t yet made a decision on what to do about the baby. Andrew asks if she has now – Joanna says yes.