"Casualty@Holby City - Part One" is the 463rd episode of Casualty and the 17th episode of the 19th series. It guest starred six Holby City regular characters including Amanda Mealing who plays Connie Beauchamp. She went on to reprise the role in Casualty as a series regular in 2014 after leaving Holby City in 2010.
Catastrophe hits Holby A&E when a truck carrying petrol crashes into the hospital. Even though only at the hospital to collect his things after been struck off, Jim is thrown into the center of the accident when he has to help Holby City character Rosie save a baby's life while Bex's life is put in danger when she takes a man to the drugs section of the hospital to help him find a doctor but it takes a sinister turn when he takes her hostage to help him get drugs for himself. Elsewhere Harry and Luke try to help out in the hospital another explosion happens leaving Bex, Jim and others lives in danger.
It's Boxing Day, and a busy shift takes a terrifying turn when a fuel tanker driver, desperate to reach his pregnant wife in the maternity unit, swerves to miss a pedestrian and crashes into the side of the building, smashing through into the reception area. As Medical Director, Connie is in charge, but she refuses to abandon the heart transplant patient she is operating on and leaves Harry to deal with the first casualties. To make matters worse, Jim has been suspended pending the General Medical Council's decision over his future, meaning he has to stand helplessly by while surgical staff Rosie, Mubbs, Donna and Ric team up with A&E's Josh, Luke, Tess and Bex. But just as they seem to be winning, Ric and the firefighters learn the tanker is leaking petrol into the basement which could have spread to Nightingale Wing, where Connie is still operating. A decision is made to evacuate - but then a maintenance man flicks the wrong switch.