Once in Shanghai, Tintin quickly becomes involved in a struggle between another branch of the opium-smuggling operation from the previous book, led by Mitsuhirato, and a resistance movement called the Sons of the Dragon, led by the benevolent Wang Chen-Yee. The Blue Lotus is notable for being the first album for which Hergé actually did a degree of research, being aided by a Chinese art student named Zhang Chongren, with whom he formed a close friendship and based one of the characters in the story on. As such, it is generally considered the point at which the series fully grew its beard.