punishment, imprisonment or in some cases death. a woman we will call yun was held prisoner for eight years in the same room as lee. they travelled five days and nights through china, managing to evade detection. they arrive in a third country we're not naming for security reasons and enter the south korean embassy. they were very nervous in the embassy, the pastor tells me. in north korea they'd learned south koreans are bad. they were filled with such mixed emotions. this is a journey thousands have taken before them, seeking asylum in south korea, a journey an unknown number can only dream of. still trapped in china's multimillion dollar sex industry. paula hancocks, cnn, seoul. >> one person who knows this plight very well is journalist julie zuog. she's written about china's sex trade and enslavement of women.