Director Danny Boyle yearns for furious motion, obvious in movies such as “28 Days Later” and “Trainspotting,” but also apparent even in the inwardly calmer pictures he's done, such as “Millions” and “Sunshine.”

So it's no surprise when the ending of that last film, a quietly suspenseful drift through the vacuum of space, gives in not only to a chase sequence, but one in which the camera is let loose to fly around, twist sideways and go upside down.

By comparison, Boyle's “Slumdog Millionaire” feels like a reward for chastity. It's set in the sprawling, chaotic bustle of India, specifically Mumbai and its slums, where Boyle's camera soars, dives, pitches and races to keep up with the near-feral children at the heart of the story. The movie is about two brothers, Jamal and Salim (played at different ages by various Indian actors), who we find in the beginning doing things boys do, like playing where they aren't supposed to, sprinting through twisting back alleys and being chased by the police.

One of them, Jamal, goes on become an unlikely winner of India's “Who Wants to Be a Millionaire?” Now in his 20s, Jamal does so well on the show, reaching the final rounds, that the show's host and producer have him arrested on suspicion of cheating. Jamal is beaten and electrocuted. No one believes a chai wallah, or tea servant, could know the answers.

The movie's setup is that it will explain how he's come to know these things, jumping back and forth in an elaborate series of flashbacks prompted by a tape recording of Jamal on the show. He's learned the answer to the show's questions through random episodes in his life. The first question, about a movie star, prompts a flashback to young Jamal working as a coin collector at a rural pay toilet, where slightly older and wiser Salim plays a trick on him by locking him in one of the outhouses right when the star arrives by helicopter on a promotional tour. Jamal is so desperate to get an autograph that he holds his nose and jumps down in the pit; later, covered in filth, he parts the crowd.

The history of Jamal unfolds this way as he and Salim make their way around the country, with the next game show question always leading to a previous episode in the two boys' lives. How did Jamal know which Hindu goddess it was? Because he had a vision one day as a child when his mother was killed by rioters. How'd he know the question about the Taj Mahal? He worked there illegally for a while as a guide. How did he know what historic American is featured on the $100 bill? It was a tip given to him by rich tourists he'd ripped off.

How'd the host know to ask the questions in the order of Jamal's life? No one knows that answer.

Boyle conjures up many fanciful sequences and arresting images during the sojourn, including a run-in with a group of ruthless men who press children into street begging, sometimes blinding them to garner more sympathy and rupees. Jamal and Salim escape, only to leave behind a young girl who Jamal will spend the rest of the story trying to find as the movie builds up a romantic interest. It's exciting stuff, all meant to illuminate something about India through Jamal's experiences. The only problem is that it doesn't. Stunning sights and sounds flood the theater, but the movie has little to say about them. What's the purpose of this look into the slums of Mumbai, where Boyle and his production couldn't have foreseen the recent horrible violence? And does it make any sense whatsoever?

If Boyle realizes the absurdities at the center of his film (cops torture someone for lying on television?) he's too busy whipping it into a frenzy to care. Artifice sticks out of the movie like the high-rises upon which Jamal and Salim stand late in the film, overlooking their former slums, but audiences also can be forgiven for ignoring it. The movie is charming and full of satisfying entertainment. Uncomfortably schematic or not, it achieves many of the basic things — romance, action and drama — that a surprising number of films this year found impossible to make convincing. Skepticism and a moral center are elusive, however, presumably lost amid the impressive, violent imagination at work, and always on the move. R 120 min. S