The movie starts about three months into an apocalyptic monster invasion, which leaves humans unable to make any sounds in case they are heard by blind predators with super-powered hearing.
Soon, the timeline moves along by just over a year – when Evelyn (Emily Blunt) is pregnant.
So given that she wasn’t expecting at the beginning of the movie, what’s the story behind her conceiving the child she ends up giving birth to in terrifying circumstances?
Presumably contraception is hard to come by when your homeland has been taken over by killer aliens, but Reddit user thebrasspig has suggested that the waterfall played a part in proceedings.
“When the dad was taking his son to the waterfall he explained that they would be safe as long as their noise is quieter than the running water,” they wrote.
“That’s why they started yelling, because it would be too quiet compared to the waterfall.
“We know that the mom and the dad conceived their child during the apocalypse, as she was not pregnant when their littlest one died.”
They added: “However it would be difficult to have sex, especially since you can’t make any noise. So that’s why I believe they [did it] at the waterfall.
“They could have all the loud sex they want, and they’d be safe. The running water would cover up any moans or groans emitted from the two.
“You could say they had sex in the nursery as it was sound proof.
“However, it’s likely they made all that after they found the mom to be pregnant, in preparation for the baby.”
A Quiet Place – directed by and co-starring Blunt’s husband John Krasinski – has amassed big critical acclaim and strong box office sales.
A sequel has been touted by studio bosses, though nothing has been made official.
A Quiet Place is out now.