Jet Li stars in this gritty, slam-bang thriller, as a sort of human pit bull held captive by a gangster (Bob Hoskins) and periodically set loose from his choke collar to dispatch anyone who gets in their way. The man's awful servitude continues until a chance meeting with a blind piano tuner (Morgan Freeman) unchains his memory and his will to rebel. Luc Besson (La femme Nikita), the screenwriter here, indulges his penchant for oddball characters; the humor ranges from sly to cartoonish, and Hoskins clearly relishes the rough-and-tumble lingo, much of which he's reported to have improvised. Pierre Morel's diving, spiraling camera keeps pace with Yuen Wo-ping's rapid-fire fight choreography, all smartly directed by Louis Leterrier. R, 103 min. Burnham Plaza, Century 12 and CineArts 6, Chatham 14, Crown Village 18, Ford City, Gardens 7-13, Lake, Lawndale, River East 21, 62nd & Western, Village North, Webster Place.