Bruce Lee, My Brother is a dramatic biopic of the eponymous martial arts legend as told by his younger brother, Robert Lee. Based directly from the book "Memories of Lee Siu Loong", which is authored by Lee's siblings (Phoebe, Robert, Agnes and Peter),[3][4] it revolves around Bruce Lee's life as a rebellious adolescent in Hong Kong before he sets off for the USA and conquers the world at the age of 18 with only US$102 in his pocket. As a young man, Bruce grew up in an affluent family. Entering the film industry at an early age, he gained fame as a child actor. Outside the home and studio, he was rebellious; he spent time engaging in street fights, dancing with lady friends, and hanging with his buddies, Kong and Unicorn, the latter a fellow child actor who would later appear in Fist of Fury and Way of the Dragon. Invincible as he is as a street fighter, Bruce's romantic escapades are not as smooth and successful. He is head-over-heels in love with Pearl, only to realize his mate Kong shares the same passion. At a cha-cha dancing tournament, Kong tells Bruce his intentions of leaving Pearl so Bruce himself can have her, damaging their friendship. Bruce is unable to come to terms with Kong. Against his father's wishes, Bruce studies the Wing Chun martial arts style instead of Tai-chi and tastes his first public triumph at a tournament with his kung fu skills. On the eve of his triumph, he learns that Kong has become a drug addict. The same boxer whom Bruce defeated at the ring informs him of his whereabouts. Bruce rumbles the drug lord's den together with Unicorn to rescue Kong, but the drug dealers confront them. Their actions cause a massive chase sequence; although Bruce and his friends survive, Kong would later die from his drug overdose. Bruce himself became the target of both the Triads and corrupted cops who want him in jail. To save his life, Bruce's father has no choice but to send him off to San Francisco, California.

In late 19th-century New Mexico, Samuel Jones reappears hoping to reconcile with his adult daughter Maggie Gilkeson. She is unable to forgive him for abandoning the family and leaving her mother to a hard life and early death. This situation changes when Pesh-Chidin and a dozen of his followers (who have left the reservation) pass through the area, ritualistically killing settlers and taking their daughters to be sold into slavery in Mexico. Among those captured is Maggie's eldest daughter, Lilly. Maggie's rancher boyfriend Brake Baldwin was among the settlers killed. The U.S. Cavalry refuses to help retrieve the captive women as its resources are tied up conducting forced relocation of captive Native Americans. This leaves Maggie, her father, and her younger daughter Dot alone in tracking the attackers. The group unexpectedly meets up with Kayitah, a Chiricahua, and an old friend of Jones, who also happens to be tracking the attackers with his son Honesco, because among the captives is a young Chiricahua woman who is engaged to Honesco. After the two agree to join the group, and Maggie treats Honesco's injuries, Kayitah informs Maggie that Jones had been a member of their Chiricahua band where he gained the name Chaa-duu-ba-its-iidan, (“shit for luck”) during his wanderings. It is finally with the combined efforts of the two families that they are able to free the women, at the cost of Kayitah's life, and immediately flee to the mountains with the kidnappers behind them. Knowing they have no other choice but to stand their ground, the group fights off the remaining kidnappers including Two Stone. During the battle, Jones fights El Brujo, the one responsible for kidnapping his granddaughter. When Brujo attempts to kill Maggie with a pistol, Jones sacrifices his life to save his daughter as both he and Brujo fall off a cliff to their deaths. Maggie shoots at the last remaining kidnappers to scare them off. She realizes her father's love for her and finally forgives him.