A call comes in from the police saying a young man has collapsed outside a nightclub and isn't breathing. It's a category one emergency - the highest priority - meaning there's an immediate threat to life. A young woman is having a sickle cell crisis. This genetic condition makes her normally round blood cells form a sickle shape, sticking together and causing excruciating pain. A woman has the highest blood pressure that one of the paramedics has ever seen, and she needs to go to hospital urgently. A former soldier collapses and is trapped behind a door, and a woman has crippling chest pains. Her condition is a medical mystery that can only be solved with a trip to A&E.