Man Gets Locked In a House Full of Women in a Post-Apocalyptic World

A stranger in silhouette is seen nearing the glasshouse at the start of the movie. But then gunfire is heard again, and he passes away from his injuries. Soon, it becomes clear how the family residing in this glasshouse uses the stranger's bodily parts to help them survive.

The corpse is placed on a stretcher in front of the three sisters, Bee, Evie, and Daisy, who then cut it open to salvage any organs they can use to make compost for their kitchen gardens. The body is subsequently covered in a jute rug and interred in a garden plot.

Then, we see their brother Gabe attempting to remember the nightly game he and Daisy perform. It is evident from their discussions that Gabe has previously been exposed to the Shred and has suffered memory loss as a result of the virus's effects.

Bee loves to shoot at these outsiders who wander into their domain only after she has taken a good look at their faces, as Daisy and Bee discuss in their conversation. She appears to be watching out for Luca, the brother who long ago abandoned the family. Soon after, the Mother, the matriarchal head of the home, can be seen talking with them about their day.

The dead are placed on a table between them, and they also conduct an odd ritual that is specific to the family. It is a practice designed to aid in their story-remembering and serve as a defense against the Shred. Everyone appears to be moving in unison, humming melodies, carrying out their tasks, and—most importantly—remembering.

One fateful day, Bee ventures into the forest to perform sentry duty and saves a stranger who is hurt. Daisy tells them that by their rules, he was terrified once inside the Sanctuary while the Mother is furious with her. While they wait for him to regain consciousness, they minister to his wounds.

The Mother questions the Stranger about his whereabouts and how he is still able to recall everything the following morning after being exposed to the Shred. He was attacked on his route, but as it turns out, he's immune to it, and Bee's kindness saved him.

The disturbing family customs are revealed as the Stranger begins to feel better. He seems to be taking an odd interest in Bee, who appears to think that it could be their missing sibling, Luca. Evie is skeptical and cautious, though. She is seen urging Bee to reevaluate her trust in the Stranger, who appears to be attempting to have a sexual relationship with Bee.

By chatting to Daisy about animals, he charms her, but Gabe acts strangely violently around him. Additionally, it appears that The Stranger is asking questions about Luca, Evie's hidden memory capsule, and the pendant they always wear.

One day, while Bee was serving as sentry, they got close bodily. Later, Evie witnesses the Stranger and Bee engaging in sexual activity. During the family rite, she is furious and lashes out at him before he shows off Luca's pendant, which he had earlier taken from Evie's box.

The Mother quickly clarifies that everyone in the Sanctuary serves a purpose, and she was using the closeness between the Stranger and Bee to introduce a new life into their midst.

The Mother tells Bee during their conversation that she will shortly remove the Stranger from the sanctuary because he has fulfilled his mission. Following an emotional breakdown, Bee tells him the Mother's plans and promises to follow him wherever he travels. When Evie is washing their underwear, she sees that Bee has missed her period, which serves as further evidence of her pregnancy.

Soon, we find out that when Gabe was younger, Evie had exposed him to the Shred when she had been careless and let him wander outside without a mask. Evie was constantly plagued by remorse over failing to protect her brother from the Shred, which is why she was so protective of the family.

Later, we see Gabe attempting to coercively kiss Evie, but she pulls away from him and chooses to please him. That is how far she is willing to give in to her remorse. Another violent outburst from Gabe in the company of the Stranger results in the breaking of one of the glass walls, alarming the family.

The Mother appears to the Stranger near the conclusion and reveals to him that she never thought he was Luca. To show that he killed her in an uncontrollable fit of rage, he finally kills her and places her on Gabe's bed's side. The Stranger purposefully exposes Gabe to the Shred as the daughters prepare the mother for the farewell ceremony, and Bee exits the building without her mask to erase a recent unpleasant recollection.

The Stranger's feelings gradually change for Evie. The family continues to reside in the Glasshouse after the Mother passes away, reconstructs its members' identities by their desires, and the Stranger joins them as Luca.