Really?The two old people aren't the kids actual grandparents but instead a couple lunatics from the local mental hospital who killed the real grandparents and took their place.
Really?
Questions for those that have seen it
How did the kids end up at the grandparents house? Why didn't the parents see them?
They took the train there alone....so their mom could go on a cruise and find happiness. And they'd never met their grandparents. The mom (and anyone else who would've known them), didn't see them because of a whole bunch of contrived, obvious red herring bullshyt reasons.