hundreds of thousands killed over the last two decades, possibly even millions. what little we know with the country's starvation horror comes from defectors. ak us angus walker talked to one of them. >> under the cover of darkness, smugglers cross a frozen river from north korea into china. taking enormous risks, and food and fuel back to their impoverished country. the footage shows an armed soldier who's been paid to cover their tracks at first light. bribing the border guards and following in the smugglers' footsteps is how people escape from north korea. now, in hiding, in south korea, this woman defected shortly after kim jong-un came to power. we've protected her identity, because she had to leave some of her family behind.