Earth tech has developed as far as it can within constraints of the solons preventing new discoveries - limited interstellar flight is possible based on 20th century nuclear technology, hibernation for a few hundred years is possible based on cyrogenics - this allows characters from the first book to reappear to help with preparing the coming battle with the Trisolarians still 300 years away.

A massive space fleet has been assembled and sets sail to meet a Trisolarian advance probe with massive hubris - it gets its comeuppance. In parallel a special project has been in play to get round the Solons ability to hear all human speech and see all human activity - half a dozen individuals have been selected and given carte blanche to call on any resources without question to implement plans that they develop solely within their own heads.