A Deadly Secret (1980)

A guy learns a deadly secret called The Deadly Secret and everyone in the martial arts world wants to kill him for it. Luckily, he also learns some kick-ass kung fu at the same time, but still ends up hiding in a prison where his girlfriend's dad routinely tortures him for the secret. Another guy gets thrown in prison to try to get the secret out of the first guy, but they become friends and he also learns the kung fu, so the two of them get to kick lots of ass when the situation escalates. The deadly secret, when revealed, turns out to be quite dull. An interesting if not entirely logical story, good performances and above average fight scenes. Not nearly as much torture or sadism as the dvd case would have you believe, but a generally solid martial arts film with slightly elevated levels of violence.