Maybe some kind of story that ends in 9/11
For exactly that, there's 2010's "Remember Me" with Robert Pattinson. Haven't personally seen it, but for most of it it's apparently a mid level romance/drama, then bam, date is revealed in on the blackboard of the main character's sister's school and the main character is looking out the window of his dad's office which turns out to be in the North Tower. Idea behind it may be something like "each of the victims had their own ongoing story that was suddenly cut short" or something, but a lot of people felt that was shoehorned in for shock value or something
Unless it's already to the point that it's super advanced, and it was intentionally playing dumb to lull you into a false sense of security /s