PLOT! Bart (Bob Hoskins) is a vicious loan shark whose method of persuading men to pay him back involves Danny the Dog (Jet Li), a young man trained like a dog and left with the mentality of a child. Danny is a violently skilled fighter who stops at nothing to take down his targets, but only when a metal collar around his neck is removed by Bart. Once the collar is on, Danny is a harmless, withdrawn person, with very little knowledge of how to live as a socialised human, and he is constantly bullied by Bart, whom Danny perceives as his master. One day, Danny meets Sam (Morgan Freeman), a kind blind pianist, at the antique warehouse while dealing with Bart’s clients.
After the collar trick with Danny starts to fail due to its inherent limitations, Bart realizes he can end his loan shark career by entering Danny as a fighter in underground fighting deathmatches.
If Danny wins, Bart receives a hefty prize money. However, after the first fight where Danny instantly kills the current champion in seconds, Bart and his men are attacked and left for dead by some men because of the orders of one of the men that previously owed money to Bart. A severely injured Danny returns to the antique warehouse for shelter, where he is found by Sam. Danny is unconscious for two days and wakes up at the home of Sam and his stepdaughter, Victoria (Kerry Condon). Danny begins to open up to them, starting a new life with the benevolent family. The two teach Danny how to eat, read, speak, cook, go grocery shopping, and how to play the piano. Danny socializes with Victoria and Sam by hanging out with them in public areas and taking family photos. He also drastically changes with new clothes, hairstyle, and fresh lifestyle, and finally learns to live without his collar after Victoria removes it. He is drawn closer to music while spending time with Victoria, and develops curiosity about who his mother was after Victoria teaches him what it means to have a family.
