Though the alien invasion of A Quiet Place remains a mystery throughout the entire movie, and we learn very little about what these creatures want, we do slowly learn that their greatest strength is also their most glaring weakness: their sensitivity to sound.
Heavy spoilers follow for A Quiet Place.
A Quiet Place’s thrilling conclusion owes its quality not only to the unique tension created by the creatures with acute hearing that are hunting the Abbott family, but also to the simmering frustrations of the family members themselves. How these plot threads evolve over time has everything to do with the well-earned heavyhanded symbolism of a homemade cochlear implant.
It’s a stroke of irony — but also convenience — that the Abbott family’s only daughter, Regan (Millicent Simmonds), was born deaf. The family can already use sign language when the world ends, so they’re uniquely suited to surviving in a world where you can’t make much noise.
The emotional core of A Quiet Place comes from the emotional wedge driven between Regan and her father Lee (John Krasinski) after her youngest brother dies in the film’s prologue. Guilt and grief drive father and daughter apart as they all live simply to survive. But Lee still spends all his spare time researching cochlear implants, building various hearing aids for her out of spare parts.
Regan is so frustrated and depressed that she can’t appreciate it when Lee gives her a new cochlear implant cobbled together with “pieces from a stereo speaker.” She’s frustrated because these implants never work, but she wears it anyway. Later that night when a monster comes up behind her, it emits a high-pitched sound that bothers her quite a bit, but it causes extreme pain for the monsters so sensitive to sound.
Something happens that attracts the creatures to the house, and the various family members all winds up separated, scrambling to avert total disaster. There are fireworks, a dip into a vat of corn kernels, and a few reunions. But when the kids’ lives are threatened, Lee has to scream, sacrificing himself to give them enough time to get away.
Back at the house, the surviving members of the Abbott family converge on the basement, where all sorts of sound equipment is stored from when Lee tried to use Morse Code to send out S.O.S. calls. It’s here that Regan realizes the power of her cochlear implant, turning it on to create enough sonic feedback to stagger the monster, exposing its sensitive ear that Evelyn shoots.
The film itself weaponizes sound to scare the viewer, but its the characters in the movie that figure out how to literally turn sound into a weapon to take back their own lives by killing the monsters.
A Quiet Place is now in theaters.