Interesting when a movie made for people who hate the thought of having children backfires so spectacularly and makes the very people it was aimed at hate it.
A rare self own.

Happily childless Margo and Ben have gone to an air B&B cabin in the woods with Margo's friends Ellie and Thomas who have brought their two kids Lucy and Spencer.

A few comments indicate Ellie and Thomas are having issues and Ellie spends her whole time half cut. Trying to lighten the atmosphere a little avid hiker Ben suggests a trail walk. They end up at some weird building that's an abandoned bunker of some kind. While exploring it Margo finds and stairway to a deep well, Lucy and Spencer stare into it claiming they see a light.
Ellie is nervous about how close they are and Thomas makes them step back, Spencer nearly drops down a second time before they all decide to go back.

Back at the cabin the suddenly quiet kids fall into a deep sleep, while Thomas and Ben talk about how Ben wants kids and Margo doesn't,  Ellie decides to tell Margo what the deal is with the static and it seems she and Thomas accidentally had a foursome with another couple and Ellie had more fun than Thomas which has messed up the dynamic. Ellie says Thomas hasn't initiated sex since that night so Margo decides to take Lucy and Spencer for the night so Ellie and Thomas can get some alone time.
They have a nice enough evening with the still quiet kids, Spencer asking to go to the pit again and hissing when Ben tells him it's too dangerous. In the morning as Ben makes breakfast and Margo goes to wake the kids she finds they've vanished, remembering what Spencer said, Ben goes back to the building just in time to see Lucy and Spencer leap in, he looks over and vomits.
He walks back numbly to tell Margo when he sees Lucy and Spencer playing in their parents cabin

After this the film should pick up but it meanders with hammering home that Lucy and Spencer are no longer the kids they were, that Ben is on some kind of medication, some fall out where Thomas gets pissed at Ellie for telling Margo about their impromptu foursome and a facebook comments argument about how people with kids are worse than people with them.

Spencer and Lucy manipulate their situation and make Ben look crazy before faking Spencer's death and framing him. Ellie and Thomas throw him out, he wanders off to the pit and sits there.
Margo finds Spencer and Ellie have vanished and sees Lucy leading Thomas into the woods, she starts to wonder if maybe what Ben said was true, finding Ellie dying under the bed confirms this.
Lucy and Spencer begin to stalk her and she sees their shadows are actually some kind of giant preying mantises and they communicate in chittering when they talk to each other.

She almost gets away when Ben reappears and she tells him she believes him but surprise! he's now part of #teamglowingwell.

It seems that Margo has been chosen as the new queen and will be a 24/7 egg layer or whatever they do to reproduce. Very subtle movie, need a coalhammer?

Ben is ambushed by Thomas who fights him, giving Margo time to leave. On the road out, Lucy, Ben and Spencer step out in front of her car...holding hands, cementing his role as their new father.
Margo floors it and the movie ends.

10/10 for atmosphere and music
2/10 for the script, it was dire beyond belief
6/10 for the actors as they did well with such piss poor material
7/10 for concept
3/210 for execution

This needed a few more drafts, the concept is good. No-one needs a full backstory and netflix mini series about the origins of these creatures but it doesn't even tell us there ARE creatures, two kids look into a pit, they claim it glows, then their eyes glow, then they kill bugs and start chittering. I can guess these bugs were left in this walled off pit due to their possession capabilities.
Why mantises? why glow? what is their plan? is it like body snatchers but with mantises? what do they do once everyone is a bug?
Is this a legend of some kind? if it is then try to let people know what culture it's from at least.

A decent once watch but frustrating due to the wasted potential