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. While diving in a remote French lake, a couple who specialize in urban exploration videos discover a house submerged in deep waters. Their dive turns into a nightmare when they discover the house was the scene of atrocious crimes.