Villainous Hung Kung-shan (Yu Tien-Lung) convinces gullible Hang Kuei (Li Tung) that his brother Tin is working for the Qing government, when in reality it is Hung Kung-shan who is the traitor. When Hung Kung-shan kills Tin and tries to execute Tin's two young sons, Hang Kuei realises his mistake and legs it to safety with the kids, placing each boy in the care of a different monk (Buddha's name be praised!).
Twenty years later, Ehr Lang (Mang Fei), the youngest son, now schooled in crane style kung fu (and proud owner of a hairstyle copied from glam rockers The Sweet), learns the truth about his father's death and goes looking for Hung Kung-shan, now a top Qing official (who sports sideburns like well-used Brillo pads). Ehr Lang's quest for revenge eventually reunites him with his brother, a master in snake style, and together the pair work out a plan of attack to defeat the wicked Hung Kung-shan.
Secrets of the Dragon (AKA Snake-Crane Secret) is standard old-school martial arts fare all the way, a routine tale of revenge that never manages to distinguish itself from countless other similar chop socky flicks of the same era. The fighting is decent enough, with Mang Fei performing some impressive acrobatics, director Wu Ma has an amusing cameo as a drunken officer, a couple of good looking kung fu chicks with weapons provide some eye candy, and a fun scene featuring the two brothers sparring whilst balanced on water jugs offers a little jollity, but there is nothing here that serious kung fu fans won't have seen countless times before.