The aliens, what they say, why they're there... none of those things end up being that important. There's no metaphor, the daughter is meant to be a representation of the inexplicable anguish and unease she feels as time goes on. The aliens' story doesn't matter -- only that the knowledge alone of their language is enough to give the speaker the ability to transcend time.

The more I talk about it, the more clear it becomes to me that the entire story, the entire plot, everything that happens, are just put in place as a means of twisting the viewer's perspective 180 degrees, pivoting it into a completely different story. Once you know that she can circulate time, the aliens go away -- because they're not really that important in the end.

Tim