A.R. Rahman's propulsive score kicks off, and after the title flashes, we cut to Jamal as a young boy playing cricket with some other kids on an airport tarmac.
Before long, however, the police arrive to break up the party.
Jamal and his older brother Salim take off, making their way effortlessly through the labyrinths of the slum in which they live, around garbage piles, through winding alleyways, and over corrugated tin roofs—chased by a cop all the while.
To the tune of "O… Saya" by composer A.R. Rahman and M.I.A., we begin to get a picture of slum life. The camera zooms out, and the sheer size of this universe becomes apparent.
A white Mercedes rolls by, and inside we see a face that will become familiar in the second half of the film: that of the slumlord Javed Kahn.
The frenetic chase scene ends abruptly when the two boys run into their mother. She promises the cop who was chasing the boys that she will reprimand them. We don't exactly get the sense she's lying.
We cut to Jamal and Salim as they're dragged up a flight of stairs by their mother, who drops them into a crowded classroom. The students are reading The Three Musketeers.
The teacher berates them for being late. "Here come our very own musketeers," he jokes, calling them Athos and Porthos, two of the three musketeers themselves.
The teacher hits them with the book, and we cut to Jamal back in the police station sitting with the cops. They put on a tape of Jamal on the game show, asking him to explain his answers.
Watching the tape, we zoom in, entering into the studio the previous day.
Prem explains the lifelines and rules, and before long, they jump into the game.
The host asks his first question: "Who was the star in the 1973 hit film Zanjeer?"
Once again we go to flashback, where we a see a young Jamal squatting inside the stall of a slum toilet. Salim sits outside. The toilet is on the end of a rickety wooden pier, suspended over a murky abyss. The smell must be intense.
Soon a customer arrives, who's in urgent need of the facilities. Salim implores Jamal to leave and make room for the newcomer.
Unfortunately Jamal is still working, and the customer leaves. The mood changes instantly, however, at the sound of a helicopter.
We soon learn that this helicopter belongs to Amitabh Bachchan, one of the greatest Bollywood film stars of all time, on his way down to visit the people of the slum.
Fact: the real life Bachchan was actually super-critical of the film, due, in part, to its British and otherwise non-Indian origins. (Source)
Young Jamal tries to leave to visit his hero, but discovers Salim has locked him in out of spite. Desperate, he makes a game time decision, deciding that there's only one possible way to escape.
What follows is a scene reminiscent of another classic bit featured in Danny Boyle's cult classic film Trainspotting—Jamal dives into the lake of feces to escape the stall and meet his idol.
Covered in poop, an ecstatic Jamal makes his way through the throngs of adoring fans and pushes his way to the front.
Sure enough Amitabh signs an autograph. Jamal celebrates, while Salim looks on in horror.