The Beach House

Emily and Randall arrive at Randall's parents' beach house in a remote vacation town and are initially pleased by its quiet isolation. They go upstairs, have sex, and fall into a small disagreement about their relationship. The moment sets a tense tone for the trip as their dynamic begins to fray.

They discover Mitch and Jane Turner are also staying at the house. Jane is terminally ill, and Mitch hopes to give her one last happy vacation. Since there is plenty of room, the two couples decide to stay together.

After dinner, they share edible marijuana. While high, Mitch notices the water texture and the glow of microbes on the beach and trees. Jane steps outside to get a closer look, coughs, and a thick fog forms, causing Emily to become disoriented and pass out.

Emily wakes up to find Jane catatonic in the kitchen, her skin covered with lesions, and Mitch missing. The ominous absence of Mitch suggests something has gone wrong, and Jane's deteriorating state signals the early spread of the infection. The mood of the house becomes tense as the mystery deepens.

Randall and Emily go to the beach and find it completely empty. Randall grows sick and rushes back to the house. In the bathroom, he notices the sink water forming strange patterns, and on the beach Mitch suddenly appears, mutters that something feels off, and then drowns himself.

Emily steps on a washed-up Portuguese man o' war and is stung; she also sees a worm-like creature crawling in an open wound. She manages to crawl up to the house and finds Jane already sickened.

Jane is locked in the house to prevent further spread while Randall and Emily flee into the slowly thickening fog surrounding the property. The fog advances, isolating them from the rest of the house and the world outside.

As night falls, the fog thickens and Randall grows sicker. Emily finds a police car with a radio and hears an official warning to barricade themselves and not breathe the fog.

They shelter indoors as the water texture changes again. Emily turns on a TV and sees an Emergency Alert System; a broadcast explains the microbes were released by global warming. Emily proposes waiting until morning, but Randall prefers to act to avoid dying.

In the basement, Emily discovers scuba tanks that could provide breathable air and realizes they might survive with them. She also encounters a horribly mutated person feeding on a corpse.

Upstairs, Randall vomits a squid-like creature and his eyes turn white as the infection takes hold. Emily returns with the scuba gear, and when Randall attacks, she defends herself and knocks him out with a scuba tank, then escapes.

Emily drives away but becomes disoriented in the fog and crashes into a tree. She staggers from the car to a tide pool, breathes the fog again, and hallucinates about the microbes in the water.

The next morning, she lies on the beach not scared as the infection completes its course. A wave finally engulfs her body and drags her out to sea.