Former Hong Kong gangster Roy (Eric Tsang) returns home after three decades of exile in Brazil, hoping to settle some unfinished business before he dies. Affected by Alzheimer's disease, he hires young thug Smokey (Nicholas Tse) to act as his guide and helper as he searches for the man who put a bullet in him and stole the love of his life. Traveling through the Hong Kong underworld together, the two men form a close bond as they discuss their idealized loves and missed opportunities.