Andy Lau (A World Without Thieves, 2004, House of Flying Daggers, 2005) plays a drug lord married with two children and another on the way to his wife (Anita Yuen). Though he is a good father, husband and friend on the surface, he is evil inside. Lau dyed his hair grey for the role to give his character a look of evil. Under the director's guidance, he acted out a realistic process of drugs manufacturing. "If the audience ends up hating my character, I'll feel like I've done a good job," he said.

Koo Tin-lok (Rob-B-Hood, 2006) plays a drug addicted villain whose wife Fan, played by rising star Zhang Jingchu (pictured inset and below, Seven Swords, 2005), tries the drug in order to show her husband that giving up is possible if one is strong-minded. But she fails. She leaves the home and meets Daniel Wu (The Banquet, 2006), who falls in love with her.

The movie was shot in Thailand. Yee said he wanted to show people the danger of drugs. "Taking soft drugs is popular among today's young," he said. "Most dangerously, one out 10 people who use soft drugs have been shown to move on to harder substances." Though the theme of the movie is far from the Spring Festival's joyous atmosphere, with the A-star list and the impressive story, Protg is expected to do well at the box office.