The Great Wall of Stars

On the far side of the Moon, a 4.7-billion-year-old relic sees the light of day. Within it lies a 'Spark'—the last gift left by a destroyed civilization for those who come after. Naval engineer Lu Zheng, during a South China Sea exercise, becomes bound to the Spark. What he gains is not a warship or mech appearing out of thin air, but an entire tech tree that requires the whole nation's effort to unlock—from controlled nuclear fusion to warp drives, from electromagnetic rails to planetary shields. The Spark also brings a warning: the Star Devourer, a silicon-based collective that has consumed three hundred civilizations, is sending its harvesting fleet toward the solar system. Humanity has only fifteen years left. Fifteen years later, when the alien fleet eclipses Saturn's light, when Pluto is flattened into a two-dimensional painting under dimensional weapons, when the trenches on Mars are filled layer upon layer—Lu Zheng stands beneath the dome of the lunar base, behind him 12,000 human warships, beneath him the blue Earth. He recalls Chief Engineer Fang's words: 'The Great Wall was not built by one person.' He recalls Marshal Zhao's final order: 'The Great Wall must not fall.' He recalls the three characters Shen Xinghe wrote in his palm. This time, the Great Wall is built across the sea of stars. — Description from novelcodex.org