A Ming Dynasty officer, He Ying (Donnie Yen), was tasked with bringing a mythical time traveling device back to the Ming emperor. He was betrayed, and subsequently frozen. He Ying, Sao(Wang Baoqiang) and Niehu were frozen during a fight. They were discovered and put in cryo-statis pods and transferred to modern-day Hong Kong. During transit, an accident sets them free. The three escape into the city. Niehu and Sao are set on exacting revenge on He Ying, despite not understanding the world they are in. He Ying soon befriends May (Eva Huang), who takes advantage of his confusion about the modern world by charging him exorbitant amount of money for rent, food, and so on. Niehu and Sao unknowingly help two Indian mobsters escape the police, and as a result join the Indian mob.

It is revealed that Cheung (Simon Yam) is looking for the trio, in particular He Ying. Through various flashbacks, it is revealed that all four were blood brothers who fought side by side, before He Ying was betrayed and charged with treason. After several encounters in the modern world including meeting May's mother, fleeing custody of the police (using his master martial arts skills), and the use of technology, He Ying starts to figure out who is ultimately hunting down Cheung.