Blood Brothers is set in 1930s Shanghai, a flourishing modern-day Babylon, replete with warlords, politicians, wealthy industrialists, courtesans and gangsters. Three innocent young brothers, Kang (Liu Ye, Curse of the Golden Flower), Fung (Daniel Wu, Around the World in 80 Days) and Xiao Hu (Tony Hang), arrive in this seeming paradise in search of a better life. Enticed by the rich and powerful world of organized crime, the three brothers start down a path of no return: they are hired to do the bidding of one of the city's largest mob syndicates. When Fung begins an affair with the mob boss' girlfriend, beauty Lulu (Shu Qi, Transporter), life takes a difficult turn for all three brothers when the forbidden love affair is exposed. Friends turn against friends, brother against brother. The days of innocence have passed; the three brothers must stand up as men and make their choices.