Riley Ip directs his melodrama about a man haunted by his memories. Ailing from Alzheimer's disease, Roy (Eric Tsang) returns to Hong Kong after 30 years in Brazil to track down his former enemy, Nine Dragons. Claiming that he was previously a notorious gangster called Mountain Leopard, he enlists the help of young street tough Smokey (Nicholas Tse). Roy tells Smokey that back in the 1970s, he and his arch-nemesis were rivals for the attention of an enigmatic beauty (Shu Qi). When she seemed to favor Roy, Nine Dragons shot him and ditched him on a barge for Brazil. Yet as the hunt continues, Smokey learns that the truth is a bit different. Meanwhile, Smokey's young heart yearns for the very female cop (Kelly Chen) who once arrested him.