Casualty fans have been given a first look at the feature-length episode which will mark its 30th anniversary.
The BBC released a trailer for the special after Saturday's shocking episode which ended in a cliffhanger.
Viewers watched in horror as clinical lead Connie Beauchamp (played by Amanda Mealing) and her daughter Grace Beauchamp-Strachan (Emily Carey) plunged over a ravine in their car.
The clip for Too Old For This Shift, the milestone instalment about Holby City Hospital's emergency department, opens with a party.
Stalwart Charlie Fairhead, played by Derek Thompson, has reached 30 years of service in the NHS.
However, the joyful occasion soon turns into a sad one.
To the strains of downbeat Delilah song I Can Feel You, glasses shatter in slow motion and Charlie's cake drops to the floor.
The fate of Connie and her daughter is likely to be central to the special, which will be broadcast on August 27.
It will include scenes that will hit "the very heart of the hospital" as key characters will be put in peril, bosses said.
Fans are promised a trip down memory lane as some much-loved faces from the show's past return.
The heart-wrenching extended Casualty storyline will also see a crossover with sister show Holby City.
Holby's cardiothoracic consultant Jac Naylor (Rosie Marcel), chief executive Henrik Hanssen (Guy Henry) and Adrian "Fletch" Fletcher (Alex Walkinshaw) will play key parts in Too Old For This Shift.
Casualty is the longest-running emergency medical drama series in the world.
The 1,000th episode was broadcast on June 25 and saw the return of original cast member Cathy Shipton as Lisa "Duffy" Duffin.