Ah Chun, Mr. Little Mountain, Water Soldier, and Mummy were in danger, but fortunately they were rescued by Bak Siu Wai, the only white blood cell policeman who remained awake. Under the leadership of Bak Siu Wai, the four set out to investigate various organs, and there were many dangers. After all the hard work, everyone still had no clue. Fortunately, Ah Chun discovered that there was a stray cell that had been tracking them, and found out that the troublemaker was in the brain of the Great Wisdom King...