Sounds Suspiously like another Movie...
Children of Invention plot: Two young children living illegally in a model apartment outside Boston are left to fend for themselves when their hardworking mother disappears.
Treeless Mountain plot: In Seoul, Korea, two sisters must look after one another when their mother leaves them to search for their estranged father.
http://www.imdb.com/title/tt1143155/
Hmmmm..... I hope they're different and this is just coincidence...