Thirty-eight-year-old Lesley is rushed in when her heart stops while she is driving to work, leaving Dr Morris battle to resuscitate her and investigate why a normally fit and well woman with no known medical problems would suffer such an attack. Abigail, aged 20, is treated for a painful neck injury caused by a riding fall, and 28-year-old Laura is brought in having a severe asthma attack. It is clear to Dr Fawcett she is deteriorating fast and that her heart could stop at any moment.

A woman collapses unexpectedly during a day out with her family to an adventure park, and is left unable to move or walk. The trauma team leader diagnoses a bleed on her brain that requires urgent surgery. A neurosurgeon attempts to drain the build-up of fluid in her brain. A motorist suffers a cardiac arrest behind the wheel, caused by a large clot in an artery, and a van driver is airlifted to hospital after a major traffic collision.