The movie is about the early days of Wong Fei Hung, a real person in late-19th century/early 20th-century China whose deeds have been greatly embellished and made into dozens of films and TV series. He is the same character portrayed by Jet Li in the Once Upon a Time series.
However, the film itself has almost nothing to do with the real person. The main character uses the WFH name and his father conjures up familiar memories of a umbrella-wielding kung fu master popularized by the Iron Monkey film. Also, in the real-life tales of WFH’s heroic deeds, it is said that he took on a dock gang in his early days, which this movie loosely portrays.