A Drop of Water was a storyline in the second novel of the " Three-Body Problem " series," Dark Forest." The story mainly talked about the confrontation and struggle between the Earth civilization and the Three-Body Civilization, as well as the unprecedented survival crisis that mankind faced. The story was compact and exciting. It showed the grand scene of the war in the universe, but also deeply explored the theme of humanity, civilization, faith and so on. In the novel, A Drop of Water showed the fragility and short-lived nature of human civilization through his unique perspective, as well as the wisdom and firm belief of people in the face of extreme living environments. In addition, the plot of the story also had a profound enlightenment meaning, which made people think about the development direction and future prospects of human civilization, as well as the wisdom and actions that humans needed to take in the face of global problems. A Drop of Water is a very good story in the " Three-Body " series of novels. It not only shows the grand cosmic war scene, but also deeply probes into the theme of humanity, civilization, faith, etc. It has high literary value and depth of thought.