The last Saturday before Christmas is always a busy time for the ambulance service. Six hours into their shift and the control room has already received over 1,000 emergency calls.
It's Friday night and 320 crews are on duty in London. Reports are coming in of an armed man on the loose, but a stabbing takes priority. Across the river a second 999 call comes in for a patient who has been stabbed in the throat.
Multiple stabbings, suicide attempts, a double shooting and an explosion at a flat flood the control centre of the London Ambulance Service with emergency calls threatening to overwhelm the service.
It's payday weekend for millions in London, and ambulance crews race to the scene of a double shooting, a stabbing, a brawl involving several people and a grandmother we is in need of CPR.
This edition shines a light on mental health services and the struggles faced by others as the stories behind the sirens have a deep and lasting impact on the staff and crews of the ambulance service.
The Friday night shift takes its toll on crews in London as they deal with reports of an armed man on the loose and two stabbings. Adam and Orani are dispatched to an elderly man who is seeing things.
A high number of Category 1 emergency calls puts the region's ambulance service and hospitals under pressure. Chris and Becca are dispatched to a man with leg pain then halfway through their shift to a high-speed collision.
Kev responds to a cardiac arrest. Gary and Fabio are dispatched to a patient who has fainted at Oxford Circus Underground Station. On a day of political protests in the capital, the entire computer system used to handle 999 calls crashes.
The West Midlands Ambulance Service have to deal with the fatal consequences as Storm Doris batters the UK. Gale force winds are causing accidents, blocking roads and grounding the air ambulance.
On the busiest day of the winter so far for the North West Ambulance Service, call handler Joe receives a 999 call from a patient who says he has a hand grenade and is threatening to use it.