Yang Peng's alien series original science fiction works. The book continues Yang Peng's consistent style of creation—incredible imagination, extraordinary exaggeration, unrepeatable comedy, bizarre plots, sci-fi elements, relaxing, humorous, and thrilling fun. At the same time, courage, integrity, kindness, unity, patriotism, and environmental protection are integrated into the delightful storytelling. The theme is positive, setting a good example for the children.

Aliens have invaded Earth! This is a group of aliens from the ghost planet who cannot be killed. How to do? In this critical situation, the brave primary school student Dididi, the intelligent Dr. Guima, the wise Witch Gurit, the Hiroshima atomic bomb victim Shuiyunjingzi gathered together to form the "Save the Earth Four" group. A fierce battle with the aliens started ...