How to explain clearly what "Three-body" is about in the shortest way?

Tribody is an alien race. Because of the harsh living conditions of the planet (three suns), it is very promising to immigrate (occupy) the livable planet. Ye Wenjie, the protagonist of the first film, was completely desperate for human civilization, and sent a cosmic wave signal to the outside world, attracting three people four light years away.

Three-body people sent a fleet of one percent of the speed of light to the earth, and at the same time launched protons at the speed of light to lock in the earth's science and technology, and assisted heterogeneous anti-human beings on the earth to form three-body organizations, and implemented various plots to welcome the arrival of three-body people.

Although the earth people successfully eliminated the three-body organization, the exposed truth really made the earth people very helpless. At this time, the earth people are just bugs for the three-body organization!

People on earth are not willing to wait for death, and they have launched various self-help actions. According to the characteristics that the three people communicate by thinking (not cheating), the ladder plan and the side wall plan are drawn up.

Lonely and desperate Yun tried her best to die after giving the goddess a dream gift (a star), but was persuaded by the goddess to take part in cutting off her brain, and was sent to the three-body fleet moving forward in space by luck, and then improvised. This is the ladder plan.