Nuclear fusion, sublight speed, curvature engine, dark matter...
Humanity spent three hundred years climbing from planet to star, and then was slapped back into the abyss.
The Grie War, the Defense of Homeland, and the Death of Star City.
Every desperate situation forces a technological explosion.
There is no savior, just engineers, soldiers, and a bunch of people who "don't want to stop."
When the August Empire's millions of fleets pressed upon the border, mankind's answer was only one word: "war".
Chinese civilization does not want to be a vassal of any civilization. It has gone from passively surviving to becoming a rule-maker.
(Slow-burning science fiction, no heroine)