First, the plot is extremely silly, even when compared with other chop sockeys. A guy in a coolie hat and dressed in a black body-suit and cape goes around picking fights with kung fu teachers and their students ... and whips them so comprehensively that he doesn't even lose the hat. Students leave their teacher, seeking other teachers to improve their skills and take revenge. Each of the three finds initially unwilling teachers who neverthless are helpful. Then they go back and take revenge as a group, despite being less than ready.
More so than many others, the plot is simply a device to get the largest number of talented fu fighters going against each other.
And it works. Spectacularly well. And the title is a gross underestimate. I counted at least 20 characters who are superb martial artists. I've seen very few other films where so many different superb fighters of different styles are combined.
Highly recommended.