He entered the Walled City of Kowloon to search for the dragon but was accosted by gang members. He was surprised to learn that the leader was his brother, Hu Bak. Cheung was rescued from the gang by the Sixth Doctor and Peri Brown, who were also looking for the dragon.
When they found the dragon, they were ambushed by Bak and his thugs. Bak was absorbed by the dragon, which controlled him while he controlled it. Cheung had to fight the dragon, but it was only when he dove into the dragon that he defeated it and saved his brother. (PROSE: Exclave)