After returning from Jingjue Ancient City, Shirley Yang brought Professor Chen back to the United States for treatment, but found that eye-shaped erythema suddenly grew on his back. After Shirley Yang consulted Professor Chen, he decided to go back to China to find Professor Sun to discuss the method to get rid of erythema. After Shirley Yang returned to China, he learned that Professor Sun was trapped in the Longling Cave, and happened to meet Hu Bayi, Wang Kaixuan and Da Jinya on the way.