In 2007, a huge natural disaster known as the "Big One" has left most of California flooded. In the city of New Angeles, a powerful crime lord named Koga Shuko (Robert Patrick) owns one half of a mythical medallion known as the "Double Dragon". When Shuko learns that two young brothers named Billy and Jimmy Lee (Scott Wolf and Mark Dacascos) have uncovered the other half, he orders the entire gang population of New Angeles to go after the Lee boys.
When their adopted mother Satori (Julia Nickson) is killed during an attack by Shuko, the Lees must team with a Guardian Angel-style group of vigilantes known as the Power Corps, led by the police chief's daughter Marian Delario (Alyssa Milano), in order to avenge the woman that raised them and save the city.
This film has examples of:
- Action Girl: Marian, who's leading a band of rebels and who pretty much saves the brothers' bacon at every turn.
- Amulet of Concentrated Awesome: The Double Dragon Medallion.
- Annoying Younger Sibling: Billy to Jimmy. And also, Marian's little brother Marc.
- As Himself: George Hamilton, Vanna White, and Andy Dick are a New Angeles news team, apparently having taken jobs in TV journalism in the wake of the Big Quake. It's not entirely clear if this bit is supposed to be full-on Adam Westing or not due to how flatly it's played.
- Big Bad: Koga Shuko, also known as "Geistman" by Satori, the brothers' guardian.
- Curse Cut Short: An exchange between Billy and Koga Shuko has Billy going "Oh, sh-" before Koga Shuko interrupting him, saying "You said it." Later given a Dialogue Reversal as the brothers turn the tables on Koga Shuko.
- Decomposite Character: Marian the Distressed Damsel (with some occasional competency at times) is basically split into the movie's Marian, who took the competency aspects, and Satori, who was not that incompetent but shares Marian's fate in the second game.
- Demonic Possession: The second half of the Dragon Medallion gives the user power over the soul, which is used to evil effect by Koga Shuko, as well as to hilarious effect when Jimmy possesses Shuko at the end.
- Dirty Cop: Averted with Marian's dad Chief Delario. Shuko tries to bribe him with a suitcase full of cash to look the other way. Delario just closes the suitcase, refusing to take it, disappointing Shuko. Though he does take the money when Shuko (possessed by Jimmy) asks to be arrested.Chief Delario: I told you Shuko, you can't bribe me.
Shuko/Jimmy: It's no bribe. (offers his hands) Arrest me.
- The Dog Bites Back: When Abobo sees what he's been turned into, he gets even with Shuko by revealing his weakness to the heroes.
- Dragons Up the Yin Yang: In addition to the dragons in promotional imagery from the game, the film added various dragon-themed props.
- Elite Mooks: The Ninja Wraiths that the brothers have to fight when Shuko unites both halves of the medallion.
- Expy: Shuko may be partially based on the Shadow Master, due to his power to possess people turns him into a shadowy spectre and later transforms into a dark warrior.
- Eye Scream: A more lighthearted example happens when Jimmy pokes Smartass Mohawk on the eye with a metal bar, leaving him crying. Luckily for the man, there's a guy with an eyepatch to give him a shoulder to cry on about his loss.
- Fascinating Eyebrow: Shuko, after possessing Jimmy, as Billy fights just before the final battle.
- Gang of Hats: Every member of Mohawks, led by Abobo, has a mohawk. There are also gangs that dress up as clowns, schoolboys and postmen.
- Hypocritical Humor: The press question Chief Delario about the possibility of some of the gangs (like the Power Corps) being misunderstood. He reminds them it's almost curfew, and they depart.
- Informed Attribute: We're certainly informed the powers of the magic amulet are awesome, and Shuko's shadow powers with his half are pretty cool. But when he gets the whole thing and gains supposedly ultimate power, he loses it thanks to a brightly-lit room. And the Lee brothers getting powers from the amulet involves Shuko losing all of his, at which point they could've easily defeated him with no magic powers at all. So really, all the amulet gives the brothers is fancy martial arts outfit and let Jimmy possess Shuko to make him look like an idiot after he's already lost.
- In Name Only: An odd case; the movie keeps many character names, and even attempts to adapt some elements of it, preserving some of the villains and even the confrontation between the brothers at the end. But then there's the rest of it.
- Inspector Javert: Marian's dad believe the Power Corps are a dangerous gang, despite how many times she says he's wrong. Later, he changed his mind after seeing her daughter is one of them and saves her and the brothers from Shuko's henchgirl Linda Lash.
- Kick the Dog: Not only does Shuko blow up Satori's place with her in it, but he possesses Satori with his medallion just to make her watch.
- MacGuffin: The Double Dragon Medallion. One half, belonging to Billy, grants power over the body, while the other half, used by both Shuko and Jimmy, grants power over the soul.
- Mythology Gag: Shuko with his medallion's powers, is loosely based on the Mysterious Warrior from Double Dragon II.
- Ninja: When Shuko combines both medallions by himself, the result is Shuko turning into a shadow being which then splits into two deadly Ninja Wraiths that the brothers have to deal with.
- Police Are Useless: Even they follow curfew. Though justified, since they have neither the manpower nor motive to deal with the gangs. Averted with Chief Delario, who wishes to do more. After helping Marian and the Lee Brothers, he tries to motivate his fellow officers to take care of the gangs once and for all, but they wouldn't. Delario's second-in-command thinks he's only asking for their help to find his daughter. But he tells them his daughter and her Power Corps are doing the work for the cops. He gives them a direct order to come with him, but they still refuse so he went on his own. By the end of the film, the police now have the strength to fight the gangs rather than compromising with them.
- Recursive Canon: A Double Dragon arcade cabinet appears in the background. A Shuko-possessed Jimmy breaks it while fighting Billy.
- Red Oni, Blue Oni: Billy and Jimmy. Ironically, in complete opposition to their trademark colors, Jimmy is the more calm and responsible Blue while Billy is the more impulsive and reckless red.
- Secret-Keeper: Marc knows Marian is the leader of the Power Corps. But he tries to get something out of keeping it a secret, which Marian ignores. He hopes she'll get busted eventually. Of course, their dad does find out and Marian probably won't hear the end of it despite things working out in the end.
- Koga Shuko asks from his twin underlings: "Huey, Lewis. Any news?"
- Alyssa Milano asks, "Now Who's the Boss?"
- Marian compares Abobo to the Stay Puft Marshmallow Man after seeing his transformation.
- When Adobo complains that an experimental steroid would kill him Koga Shuko says he considers him like a son. And like a son, [he] can always have another; however, there is only one Double Dragon. One crook sells out another with almost those exact words at the climax of The Maltese Falcon (1941).
- Totally Radical: Characters constantly use slang nobody's ever used, like Michael Berryman's character calling Koga Shuko a "little snarf". Or before that when a gang member repeats a message from Shuko that, "If we don't jack in, we'll all be vapor!"
- Weaksauce Weakness: It's established early in the film that for whatever reason, Koga Shuko is sensitive to light, which is why he spends most of the film wearing sunglasses, sunglasses that conveniently disappear during the climax. After he gets both pieces of the amulet and goes One-Winged Angel, Marian gets the lights back on, stripping away all of Shuko's power just like that.
- Whip It Good: Linda Lash carries a whip.
- Wonder Twin Powers: The only way the Dragon medallion could be used in the movie without corrupting the user with its power, with Billy using one half of the medallion and Jimmy using the other.
- Xenafication: Marian, the Power Corps leader, is supposed to be the same character who gets punched in the stomach and carried off by the Black Warriors in the original game.
- You Did Everything You Could: Jimmy thinks Satori should have told him and Billy the truth about the medallion sooner. Billy defends her, saying she had no idea Shuko would find the first half and be looking for the other, "she did the best she could". Billy calls him out for it, since she was the only family they had.
- You Have Failed Me: Shuko mutated Abobo into a hulking giant for failing to steal the other half of the medallion, despite insisting he had no idea what it was.
- Your Mom:Shuko: You're weak like your father.
Billy: You're ugly like your mother!
- Your Terrorists Are Our Freedom Fighters: Chief Delario designates the Power Corps as terrorists, even though they're the most heroic gang.
- Zeerust: The film takes place in a future after a huge natural disaster has left most of Los Angeles (now dubbed New Angeles) flooded... in the year 2007.