The story begins with a scientist discovering a message from the Trisolaris extraterrestrials. A friendly Trisolarian sends her a message: "Don't answer! Don't answer!" But she is so bitter with her Cultural Revolution experiences that answers: "Come and destroy humanity! I'll help you!" She establishes a secret movement dedicated to sabotage human defense and to facilitate Earth's invasion. I find that since Ancient Greece, In all history, specially in the Ancient Greece, there are always voluntary traitors, in fact, an enemy storming a city could always be confident that a faction would betray the defense. Why is that so?
When the Chinese decide to build their Space Force, they find it natural and necessary to create a Space Force Political Department to carry on political and ideological work. They select Zhang Beihai to lead this branch and he proposes that some of the best officers should be sent to the future (by hibernation), to re-inforce the fighters that by that time may have been weakened by "defeatism" and "escapism". More than a technological fiction, Liu spends about half of the text in imagining the political and hierarchical setup of humanity's efforts to confront the Trisolarian invaders. The setup is - surprise me ! - an idealized contemporary Communist China - the book tries to convince the suffering Chinese reader (more than 1000 pages) that the current regime is good and will be going two hundred years from now. Otherwise, Liu's book may have had little chance of being published and less translated. It even could be seen as political propaganda under a sci-fi cover.