Sara Brown (Allison Caetano) is a villainess in the episode "E Uhi Ana Ka Wa I Hala I Na Mea I Hala" in episode 3 of season 10 of the Hawaii Five-O reboot.
She was an underwater welder who shot and killed her partner in crime, Jay Kahale, with a powerhead (a specialized firearm used by divers underwater) when they dived underwater to collect diamonds that went down in a plane crash in 1983.
When Five-O was investigating the murder, they found that someone went by a name Delphi Son was constantly creating new conspiracies online about the plane crash. It turned out to be Joe Ennis, who was the brother of Ron Ennis, one of the passengers in the crashed plane.
The team found Ron had stolen a heiress's jewellery worth 4.1 million dollars and hid it under his seat. Joe hired Jay Kahale to collect it before the salvage company did, and Jay made a big mistake by letting the evil villainess, who betrayed him, work with him.
Joe arranged to meet with the villainess to kill her, but she shot him in the gut and fled.
Five-O located her and started the chase. When Tani told her to stop, the evil villainess began to open fire. They got into a fight underwater, and gradually, Tani won, arresting Sara after performing CPR on her, sealing the evil villainess's fate.
