. >> narrator: jiro ishimaru is a journalist trying to expose what kim jong un's regime wants to hide: the secret world of the north korean people. he has an undercover network which covertly films life inside the country. >> (translated): obviously, it's an extremely dangerous thing to do. in north korea, even filming everyday life is considered a form of political treason. if they are caught filming, they'd be locked up and may never be let out again. >> narrator: even filming on the chinese side of the border is illegal. >> narrator: the people who work for jiro smuggle their footage across the tumen river, which divides china from north korea. the north korean border guards have been known to shoot to kill. the border has become even more tightly controlled since kim jong un took over as supreme leader two years ago, the third ruler in the kim dynasty after his father and grandfather. he inherited the world's most isolated country, where the people have no internet and the state has almost total control on any information coming in or out. even with the tight security, jiro and hi

some footage obtained by japanese journalist jiro ishimaru is featured in tonight's frontline on pbs, "secret state of north korea." here's an excerpt. >> these are pictures we want the world to see. north koreans living n. towns across the country. they risk their lives to get the footage. one of his contacts is it a states employee, but has been smuggling footage out for five years. he agreed to speak if his identity was concealed >> (translated): this is dangerous, and if i get caught, i know i'd immediately be executed as a traitor to the korean people. but i've got to do this. i've got to do this no matter what. i'm just one person. even if i have to sacrifice my life, someday, something is going to change. >> narrator: the famine which killed more than a million north koreans in the 1990s has ended. but the united nations says the country is still vulnerable to food shortages, and more than three quarters of the population don't have enough food to eat. >> narrator: over the past three years, jiro's undercover network has filmed orphaned street kids gathering in the markets begg