When a mortally wounded astronaut crashes into an isolated road-diner, the young waitress must protect herself and her customers from the oncoming alien threat!!

Well said, FFF.

I know trying to get so much across in so few words is difficult. Don't worry if you go over twenty-five words - up to about thirty-five words is acceptable, so I've been told. Maybe you don't need to mention the astronaut at this stage. How about starting with something like this: 'After being warned of an imminent alien attack, a young waitress at an isolated road-diner ... '

Ok, this sounds a bit like 'Legion":

An out-of-the-way diner becomes the unlikely battleground for the survival of the human race. When God loses faith in humankind, he sends his legion of angels to bring on the Apocalypse. Humanity's only hope lies in a group of strangers trapped in a desert diner with the Archangel Michael.

My take: South Parks "Cancelled' meets "Legion"

A young waitress and her customers trapped in an isolated road-diner must fight of an Alien TV crew and their brutal SWAT team - who must decide if humans can still kick ass and its worth to continue the ones bloody popular intergalactic sitcom Earth - now ratings have dropped dramatically.