Human civilization has left the solar system for 800 years and colonized 37 galaxies. The combined fleet is the strongest force of mankind, and AI "Zero" is the core intelligence of the fleet. Every three hundred years or so, mankind will encounter a "cleaning" - a silver fleet appears and cleans all colonial stars with precision, without occupying or communicating with them, only destroying them.
Chen Xi went through 372 cleanings, surviving to the end each time, and activating the "rebirth device" each time to go back to three hundred years ago. But she doesn't know the origin of the rebirth device, or why she can retain her memories.
