I almost gave this a rare 5!!
The story concerns the aftermath of a global war, the intervention of an alien species, and the collapse of society into mob rule. The story unfolds as it progresses, giving glimpses into key ideas without actually giving anything away.
The loss of a star? Two minor points. Firstly it almost becomes Deus Ex Machina at the end, like gloss paint on the dystopian backdrop. That made it a bit disjointed, but OK. Also the story leaves itself open to a sequel ... which doesn't seem to be forthcoming! However, it still works as a standalone in its own right.