While diving in a remote French lake, a couple of YouTubers who specialise in underwater exploration videos discover a house submerged in the deep waters. What was initially a unique finding soon turns into a nightmare when they discover that the house was the scene of atrocious crimes. Trapped, with their oxygen reserves falling dangerously, they realise the worst is yet to come: they are not alone in the house.
A horror-thriller centered on a woman living with "face-blindness" after surviving a serial killer's attack. As she lives with her condition, one in which facial features change each time she loses sight of them, the killer closes in.