Returning home later she is very unsettled as she sees a number of odd things that make her recall that night in her youth.
Adelaide tells Gabe about how that night she got separated from her parents and met her own exact doppelganger. She persuades Gabe they should leave but just then the lights go out and there's a family of four, just like the Wilsons, outside the house waiting sinisterly.
Jordan Peele's follow-up to "Get Out" leans into weird and creepy.
Mixing a bit of violent home invasion with shades of Invasion of the Body Snatchers and zombie movie style infrastructure collapse (call the cops, but nobody comes) it's fun, tense and Lupita Nyong'o is excellent in the two roles. The family's initial reluctance to resort to the violence they need to survive and growing comfort with it is excellent.
It is however a cool idea/metaphor in search of a justification for its existence and they infodump a load of stuff in a set of linked scenes near the end to explain things. When you need to do this instead of it organically happening you know it was too convoluted/implausible to begin with.
Show don't tell, 7/10.
A decent creepy thing but once the explanation starts coming out it pushed my bullshit button in a way it wouldn't if they'd explained less. It's quite possible this was off the back of a test audience more concerned with answers than I am.