The British Film Institute calls Tongpan "One of the most important "third world" films of the decade. It is based on the real life experience of a farmer from the poverty-stricken Northeast region of Thailand. Tongpan and his family are forced off their land when a dam built nearby caused their farm to be flooded and left it parched in the dry.

In a story alternating between the past and present, Laura Preston flies to Thailand to meet a stranger claiming to be her lost brother, who disappeared when the Preston family lived in Bangkok forty years ago.