An unexpected spike in 999 calls means drastic action must be taken.

Episode two joins the staff in the nerve-centre control room on the night shift - when amongst the thousands of calls they receive, they also have to contend with hoaxers, frequent callers and run-away patients.

The London Ambulance Service braces for a demanding weekend shift.

In this episode, one of the 187 calls West Midland Ambulance Service is dealing with at 20:31 on Saturday night, is from a distraught wife whose husband has suddenly collapsed - his heart stopped - on their lounge floor, the TV is still on. The call handler must stay cool-headed and coach the woman and her daughter over the phone in how to do CPR whilst ambulance crew Katie and Sarah race to help.

In this second episode, one hour into the night shift with West Midlands Ambulance Service and the control centre is already on its third cardiac arrest. The highly-skilled MERIT team are administering care to a patient who has been stabbed and is bleeding heavily, the fourth stabbing victim the service has dealt with so far this Friday night.

In this episode, 71-year old Mick, who's already retired once but rejoined after missing life on the road, and his crew-mate Dave are dispatched to help a woman who called for pain in her tummy, but is actually having a massive heart attack and urgently needs the expertise of the specialist Cardiac Centre at Royal Stoke Hospital.