A scientist at a top-secret weapons facility creates a weapon that he then regrets. So he steals it and gets on a plane to Mexico with the head security agent’s family, hoping that having the family along will restrict the agent’s options. But the response is out of the agent’s hands when the president orders the plane shot down. Fortunately, the scientist activates the weapon just before the missiles strike the plane—well, partly fortunate: One copy of the plane and most of the passengers are blown into yesterday, while the scientist and the agent’s family survive in a null space that will first eat all of California and then the rest of the universe.

So, why were the dead passengers and one copy of the plane blown into yesterday? I never did figure that out; it had no bearing on the movie, except perhaps the filmmakers were Donnie Darko wannabes, and it provided a cheap wrap-up at the end.