Flash Legs, aka Shaolin Deadly Kicks, is a 1977 Hong Kong martial arts action film starring Dorian Tan and Lo Lieh.
A gang of robbers (known as "The Eight Dragons") have infiltrated a local residence in an attempt to steal a map. Upon its successful retrieval, when the bandits are about to make their getaway, the lights suddenly flick on, and they are accosted by the owner of the house (the map, presumably, is his as well). The owners of the house are quickly disposed of, and The Eight Dragons make off into the night with their map.
Because of the robbery not being executed as smoothly as planned, The Eight Dragons become paranoid about actually seeking the treasure divulged in the map, and decide to hold off until the heat blows over. So they divide the map into eight pieces, and promise to meet again in three years and collect their fortune.
It isn't too long after the temporary break-up that one of the Dragons (Husky) is arrested in an unrelated robbery (which, basically, was a desperate attempt to cover his extensive tab at the local brothel.. In jail, he meets Fong Yee (Dorian Tan), and together they devise an ingenious plan to escape. Actually, one of the other prisoners pickpockets a guard, gets the key to the cells, and lets them go.
Approximately ten minutes after their escape, Husky discovers that Fong Yee is actually an undercover cop out to infiltrate The Eight Dragons and recover the map. After killing Husky Dragon, Fong Yee recovers the first piece of the stolen document.
One by one, Fong Yee confronts each member of The Eight Dragons, and for the most part, kills them but gets captured by one of them, however he eventually escapes without the map pieces. Fong returns the next day, disposes of his captors, and recovers their respective pieces of the map. Unfortunately, however, he is stabbed in the process.
With the knife still embedded in his back, Fong Yee wanders into the woods and passes out. He wakes up in the house of the girl he previously saved. The recovery process proves slow; Fong not only needs to mend his body, but also regain his kung-fu prowess as well. But unbeknownst to the young couple, her father (Wong Hap), ironically, turns out to be one of the few remaining Eight Dragons, and a final showdown between him and Fong is inevitable. The #2 of the Eight Dragons arrives (Lo Lieh) as the reunion is close. The father chooses to repent and give up the map so that he can live in peace and not reveal his past to his daughter. Lo Lieh kills him and steals the map. Fong Yee and the daughter hunt down Lo Lieh to get the map as well as revenge.