Watch: Indian Boy Runs 48 Marathons Before Age 5

HBO's airing the documentary 'Marathon Boy' tonight at 8.

If you get HBO, tune in tonight at 8 p.m. The network’s debuting this insane documentary called Marathon Boy, the story of a boy from the slums of India who runs 48 marathons before turning five years old.

Budhia Singh was sold into slavery at age 3 by his impoverished mother. Total cost: about $16 dollars. Biranchi Das, who runs an orphanage, buys him out of slavery, and soon discovers that Singh has a talent for runner. Without spoiling the entire plot (the Wall Street Journal does a pretty good job of that over here), Das becomes his coach, with dreams of sending Singh to the Olympics. The kid proceeds to run nearly 50 marathons, and even completes a 42-mile run in 93-degree heat … before almost dying.

The story seems incredible, infuriating and fascinating all at the same time. Check out the trailer below.