A horror movie released before 2009 whose name I can't remember but I know the plot

A man goes to a forested area in search of his missing father. He encounters his father’s former colleague, who later reveals himself to be the man’s actual father. He traps his son in a cave/tunnel that was once used by a king to trap a maid and her child, and it is haunted by the ghost of the woman.

The maid was pregnant with the kings child and hence the king had her banished but after a few years she returned with their son so the king proposed marriage to which she happily agreed and went to the forest with her little boy to collect flowers. Unbeknownst to them the king ordered his minister to trap the maid and their little son in a cave/tunnel.

was this an asian horror film?