From Microsoft: Double Dragon is the story of Billy and Jimmy Lee, twin brothers who learned to fight on the cold, tough streets of their city. Their expert knowledge of the ancient martial art of Sou-Setsu-Ken, combined with their streetwise outlook, means that they're two of the most formidable combatants ever to walk the streets. Billy and Jimmy will use their feet, fists, elbows and whatever weapons come to hand to defeat the gang that kidnapped Billy's girlfriend.