The six part crime drama set around a sleepy village in Loch Ness finally came to a head when it turned out that Kieran Whitehead (played by Jack Bannon) was actually masquerading as his brother Jordan, who has been in a coma for the entire series.
The body in the loch was actually the brothers’ violent father, and 24-year-old Kieran killed him after suffering his abuse since he was a little boy.
The pair’s mother Bea Whitehead (Anita Vettesse) made a choice to give her son a fresh start by swapping their identities, but the plan failed when her husband returned and set in motion Kieran losing control before killing five people.
The moment when Kieran reveals the truth to school friend Evie (Shona McHugh) and daughter of Detective Annie Redford (Laura Fraser) comes when he realises that his father’s body has been found and his secret is at risk of being exposed.
ITVThe Loch: Tonight's finale saw the killer revealed in a surprise twist
ITVThe Loch: Kieran's brother Jordan turned out to be the real Kieran
ITVThe Loch: Evie was horrified to discover her friend and lover was the killer
Why do you have to be like the others? Trying to burrow into my head
Not thinking clearly, Kieran tells Evie: “What you did… Every time I get a glimmer of hope he shows up.”
After a confused Evie continues to question him on what he means though, Kieran completely turns on her, saying: “Why do you have to be like the others? Trying to burrow into my head. That body, that was my father.”
Viewers took to Twitter to express their surprise at the reveal, as one person posted: “Well the 'Loch' I was not expecting on who it was. Certainly a few twists,” while another said: “I read and watch a lot of crime fiction but I didn't see the twist coming in The Loch. Excellent stuff @ITV. Bravo to the writers.”
While one excited fan praised the ITV show, saying: “TheLoch was a brilliant mystery. Kept me guessing until the end. Roll on series two!” Another person wasn’t so enthusiastic: “@Stv #TheLoch Very cheesy ending. Overall no more than a 5/10. It certainly wasn't gripping.”
ITVThe Loch: Annie may have killed Kieran when she saved her daughter Evie from him
“I actually enjoyed that! Far fetched yes, but kept us guessing and bet no one guessed the Kieran, Jordan identity swap.. #TheLoch,” one viewer admitted.
The episode also saw Dessie Toner (Conor McCarry) exonerated of murder, and left the window open for a return as the body of Kieran was left undiscovered in Loch Ness after Annie injured him.