|By Source, Fair use, https://en.wikipedia.org/w/index.php?curid=61424261, courtesy Vertigo Publishing|
A House Hunters episode gone really bad. An ordinary couple Tom (Jesse Eisenberg) and Gemma (Imogen Potts) decide to take a tour of the latest housing development. They are led there by a peculair acting man Martin (Jonathan Aris) who shows them the house and then disappears. When Tom and Gemma try to leave they discover there's no way out of the neighborhood. Trapped.
Before all this happens we're shown a nature sequence of the cuckoo bird's parasitic birthing method of leaving their eggs in another bird's nest, disrupting the flow of nature. Gemma, a teacher, comforts a child who finds a baby bird pushed out of its nest by the cuckoo, telling the child that sometimes nature is cruel. She'll soon learn the lesson all too well.
Psychological horror may the most potent subgenre because it gets into your head. Vivarium got under my skin, a movie that may bounce around in your head for a couple days. Slightly altering the way you see the world. Accepting they're stuck, Tom and Gemma begin a daily existence, being provided with food from an indeterminate source. Both come to accept they are in some version of hell, and it's not the zany Tim Burton afterlife of calypso music and shifty exorcists. Then a baby is dropped off who quickly turns into a creepy kid, and eventually an even creepier young man. Imagine having to take care of something evil. Gemma tries to connect with the "child" while Tom begins to lose his mind, spending his days digging a hole in an existential attempt to escape.
A slight spoiler, but the film never shows its cards. It 's unnecessary. I have an idea of what's going although it's never explicitly revealed. I suppose there are other possibilities. Metaphors abound throughout, namely, life is predictable and boring as we gradually settle into our roles. A dark theology is embedded into the movie, the universe/nature is malevolent. Nature makes a mockery of human ambition. I'm not pessimistic enough to believe that. Yes, we may all live lives of quiet desperation with little to show for it at the end. But at least there's the possibility of meaning and experiencing joy through the power of memory, a notion the film at least tries to suggest.