This was Bruce Lee's first film done entirely in Hong Kong. The director gave him complete control of the script and his own role and this was the start of Bruce Lee's philosophizing on film.
Bruce Lee is off to work in a chinese ice factory and has to find co-workers who've gone missing. A treacherous big boss who is an opium smuggler and womanizer leads him down the garden path, until he finds out the truth.
Of course he settles scores with his remarkable fists. But, perhaps for the only time in his cinematic life, he hesitates to fight (because of a promise to his mother:). And gives himself up to the police for a girl he's soft on.
Ever after, Bruce Lee was larger than life and more emotionless. Here he's sweeter than in his other movies, though his remarkable talent is evident.