The Survivors is a chilling limited series by Netflix that showcases the murder cases in a coastal town of Tasmania. But the lives of the residents are turned upside down when they discover that the case is intertwined with another murder that happened 15 years ago in the town of a girl named Gabby. The show lifts the curtain from the years-long mystery and the dark turn of events that happened on that day, ultimately revealing that the killer behind both cases is the same person: Sean Gilroy.
Years ago, Sean and Gabby had ended up in a cave together ahead of the deadly storm. Sean tried to kiss Gabby inside the cave but was rejected. Unable to stand by the insult, he left her in the cave alone, and she died, drowning in the storm. Read on to know the complete story behind the killing of a teenage girl, Gabby, from The Survivors.
Here is the complete story behind Gabby's murder in The Survivors

It was an ordinary day when Gabby was looking for Kieran and wanted to go to the caves. Sean accompanied her as he was aware of the complicated path to the caves. Gabby put her trust in him, but things took a dark turn when they entered the cave. Sean had feelings for Gabby, and in the cave, though they didn't find Kieran, they carved their names on the cave walls. Misreading Gabby's friendship as flirtation, Sean tried to kiss her, which upset Gabby. She told him she wanted to leave. Sean "feels stupid" after the incident and, without thinking, storms out of the cave.
This leaves Gabby alone in the cave, which is filling rapidly with water from the storm while Gabby is stuck, unable to find her way out. This takes her life, and the residents think that she is simply swept off by the storm, just like how the storm also took the lives of two other boys, Finn and Toby.
How do the residents get to know the truth behind Gabby's death in The Survivors?
Kieran had left the town after the incident, and after years comes back with his partner and Gabby's childhood best friend, Mia. But shortly after that, another murder occurs: Bronte, who was researching the years-old case of Gabby. This puts Mia on edge and fuels suspicion of these two cases being connected somehow.
Sean had to kill Bronte as she was too close to the truth behind Gabby's death, but this time Sean couldn't escape the crime scene and was finally held accountable. Sean had taken Bronte to the sea to take some photos and showed her his and Gabby's names carved inside the cave. When Bronte starts to get uncomfortable and tries to head home, she is hit by the flashlight.
Finally, in The Survivors, Sean Gilroy is caught not for one but for both of his crimes, and Brian, who was falsely accused, is free. The residents finally perform a combined ceremony for the two departed souls, and Gabby’s mother finally finds peace as the true culprit faces justice.