An opening prologue set years before the events of the first film tells that Lord Shen, the scion of a peacock clan that rules Gongmen City in ancient China, seeks to harness fireworks as a weapon. After discovering from the court's goat Soothsayer that "a warrior of black-and-white" will defeat him if he does not change his ways, Shen leads an army of wolves to exterminate the panda population to avert the prophecy. Shen's parents are horrified at this atrocity and exile their son, who swears revenge.
The story is set in the Valley of Peace, a fictional land in ancient China inhabited by anthropomorphic animals. Po, a giant panda, is a kung fu fanatic who idolizes the Furious Five — Tigress, Monkey, Mantis, Viper, and Crane — a quintet of kung fu masters trained by the red panda Master Shifu. As he helps his goose father Mr. Ping in his noodle restaurant, Po is unable to pursue his dream of becoming a kung fu master himself.
Twelve-year-old Dre Parker and his mother Sherry move from Detroit to Beijing after Sherry gets a job transfer at her car factory. After a day in a park, Dre develops a crush on a young violinist, Meiying, who reciprocates his attention, but Cheng, a rebellious kung fu prodigy whose family is close to Meiying's, attempts to keep them apart by violently attacking Dre, and later bullies him at school. During an attack, the maintenance man Mr. Han comes to Dre's aid, revealing himself as a kung fu master.
The movie begins by Jackie Chan telling the story of the Old Summer Palace and its looting and destruction by British and French soldiers in the Second Opium War. Among the treasures stolen are twelve bronze heads of the animals of the Chinese zodiac.
Lee (Bruce Lee) is a Shaolin martial artist from Hong Kong who possesses great philosophical insight into martial arts as well as physical prowess. He receives an invitation to a martial arts competition on an island organised by the mysterious Mr. Han (Shih Kien). Lee learns from his Sifu (teacher) that Han was also once a Shaolin student, but had been expelled from their order for abusing their code of conduct.
Sing (Stephen Chow) is a master of Shaolin kung fu, whose goal in life is to promote the spiritual and practical benefits of the art to modern society. He experiments with various methods, but none bear positive results. He then meets "Golden Leg" Fung (Ng Man-tat), a legendary Hong Kong soccer star in his day, who is now walking with a limp, following the treachery of a former teammate Hung (Patrick Tse), now a rich businessman.
Ma Hon Keung (Jackie Chan), a Hong Kong cop comes to New York to attend the wedding of his Uncle Bill (Bill Tung) who introduces his new, African-American wife Whitney to him down at his supermarket, which he owns and has sold to Elaine (Anita Mui). Uncle Bill's friend, Steven Lo (Jamie Luk), loans him a vintage automobile for the wedding. Later that night, a street gang starts a motorcycle race near Uncle Bill's apartment. They are about to run over his friend's car until Keung jumps down and stops them. He soon starts a rivalry with the street gang when he drives them away from the supermarket that they were robbing and vandalizing. This starts a series of brawls in which the bikers try to corner Keung and finish him off. When a member of the street gang named Angelo (Garvin Cross) gets involved in an illegal diamond deal gone bad and steals the diamonds, the small-time gangsters become the victims of a much larger and more effective criminal syndicate led by White Tiger (Kris Lord). While running away with the diamonds, Angelo leaves them in a cushion, which is unknowingly used by Keung for the wheelchair of a disabled Chinese American boy named Danny (Morgan Lam), who is raised by his elder sister Nancy (Françoise Yip), a lingerie model/dancer who works in a seedy bar and is an associate/girlfriend of the bikers. Keung befriends Nancy and advises her to stay away from crime. When the gangsters see this, they chase Keung and Nancy. After failing to confront Keung, the bikers turn up at Elaine's supermarket and start vandalizing it, during which two of Angelo's men are captured by White Tiger's men, who turn up at the supermarket in search of Angelo. Angelo's colleagues are unaware of his diamond heist and one is executed in a tree-shredder; his remains are given back to the other gangster to show to his friends as a warning to return the multimillion-dollar goods. In the meantime, Keung and Nancy go to the bikers' shed after the latest supermarket attack, and Keung defeats them in another brawl, at which point the shredded remains are brought back.
Whilst working for the CIA, Chan Ka-kui (Jackie Chan) is assigned to follow leads of a nuclear smuggling case. He follows a woman named Natasha to Ukraine, when he realizes that she had been hiding vital information, Ka-kui calls for backup and she is later arrested. However, Natasha's partner is an unknown man, who turns out to be Jackson Tsui (Jackson Liu), a Chinese American nuclear scientist with CIA links, suspected of stealing a nuclear warhead. Ka-kui follows Tsui to a restricted area, and after a trap set by Tsui, the CIA agents together with Ukrainian authorities engage in battle. Ka-kui finds a briefcase which contained evidence from Tsui, but as he is chased by unknown forces, Ka-kui loses the briefcase as he falls into frozen waters.
Ka-Kui is the "supercop" of the Hong Kong police, with amazing martial arts skills. He is sent to Guangzhou, where the Chinese police force's Interpol director, Inspector Jessica Yang (Michelle Yeoh), briefs him on his next assignment. The target is Chaibat, a drug lord based in Hong Kong. To infiltrate Chaibat's organization, Ka-Kui is to get close to Chaibat's henchman Panther, who is in a Chinese prison. Ka-Kui, posing as a petty criminal prisoner, manages Panther's escape with the connivance of the guards. Grateful Panther invites Ka-Kui to go with him to Hong Kong and join Chaibat's gang. Panther meets up with some of his other men, and vouches for Ka-Kui. The group heads for Hong Kong.
In nineteenth century China, Jungle Village is home to several warring clans. The village blacksmith creates deadly weapons for the clans, intending to use his payments to purchase the freedom of his lover Lady Silk, and leave the village. The region's governor tasks the Lion Clan's leader Gold Lion with protecting a large shipment of gold that must pass through the village. Gold is betrayed by his lieutenants Silver Lion and Bronze Lion, who plan to steal the gold. They use the chaos ensuing from a fight with the Hyena Clan to allow their co-conspirator Poison Dagger—the governor's aide—to assassinate Gold, after which Silver becomes the Lions' leader. Gold's son Zen-Yi learns of his father's murder and sets off to the village to seek revenge.
During the Qing Dynasty, Han Chinese and Manchu people were not allowed to marry each other. The Emperor commands Ko Hung (Eddy Ko) to kill his wife. However he refuses, and he has to see his wife die and engages in a battle with the Sorcerer Bat (Yuen Shun-yee). To escape, he also takes the infant prince with him. Ko Hung later accidentally kills the prince. However, he then finds an infant under a tree whom he adopts and names him "Shu-kan", which is literally translated as "Tree Root". To cover up what he has done, he puts the prince's jade on Shu-kan. Over a decade later, the Sorcerer Bat tries to kill Ko and tries to kidnap Shu-kan and pass him off as the prince. Ko becomes heavily injured, and Shu-kan (Yuen Yat-cho) goes to find medicine to heal him where he meets two elderly Taoist priests, Kei-moon (Bryan Leung) and Tun-kap (Yuen Cheung-yan). Kei-moon and Tun-kap are disciples of the same master (Yuen Siu-tien), and are always quarreling with each other. There the two teach Shu-kan their martial arts and magic skills. The Sorcerer Bat tries hard to get rid of the two to get Shu-kan, but later he manages to kill Tun-kap. Kei-moon then tells Shu-kan to enter a competition to obtain the Supreme Command. Shu-kan, using the skills he learned, enters the competition where he goes through many different obstacles before he faces off with the Sorcerer Bat. He eventually kills the Sorcerer Bat, wins the competition and brings the supreme command with him. As he returns, he and Kei-moon discover that Tun-kap actually faked her death to fool them to obtain the Supreme Command. The two elders then quarrel again over the Supreme Command. They then decide who will take it in a game of Rock-paper-scissors. First, they both hand gesture "rock", then "paper" but Shu-kan gestures "scissor" and beats them both. With the Supreme Command, Shu-kan commands them to stop quarreling.
The film is set in Foshan, China sometime in the late 19th century during the Qing dynasty. Liu Yongfu, the commander of the Black Flag Army, invites Wong Fei-hung on board his ship to watch a lion dance. Some sailors on board a nearby American ship hear the sound of firecrackers and mistakenly think that Liu's ship is opening fire at them, so they return fire and injure the dancers. Wong picks up the lion head and finishes the performance. Liu comments about the perilous situation China is in, and then gives Wong a hand fan inscribed with all the unequal treaties signed between China and other countries.
Chen Zhen (Jet Li) is attending class in Kyoto University when some Japanese karate students from the Black Dragon Clan burst in and attempt to force him out because he is Chinese. Mitsuko Yamada (Shinobu Nakayama), one of Chen's female classmates who has a crush on him, along with Chen's professor and other students, speak up for him. The thugs turn violent but Chen easily defeats them using a variety of controlled Chin Na techniques. The Japanese thugs' sensei, Funakochi Fumio (Yasuaki Kurata), who is also Mitsuko's uncle, arrives to take control of the situation and apologizes for his students' behavior. Fumio is impressed by Chen's skill and converses with him, and Chen learns that his master Huo Yuanjia has died after losing in a match against a Japanese martial artist. Chen is distraught after hearing the bad news and he leaves for Shanghai immediately.
Jackie, a.k.a. "Asian Hawk", is a former musician who becomes an adventurer and treasure hunter. After successfully stealing a sword from an African tribe, he has the weapon auctioned before it is won by May Bannon, the beautiful daughter of Count Bannon. He is reunited with his former band mate Alan, who seeks his help as his girlfriend Lorelei has been kidnapped by an evil religious cult as a means of acquiring Jackie's services. The cult possesses two pieces of a legendary armour called the "Armour of God", and they intend to have Jackie bring them the three remaining armour pieces, including the sword. Jackie and Alan strike a deal with Count Bannon, who is in possession of the three armour pieces: they will borrow the armour pieces for their quest to rescue Lorelei with a promise to complete the armour for the Count, on the condition that May accompanies them.
Dragon (Jackie Chan) tries to send a love note to his girlfriend via a kite but the kite gets away and as he tries to get it back, he finds himself inside the headquarters of a gang of thieves who are planning to steal artifacts from China.