I guess you would need to check the Position of the current character and according to the y or x position (don't know what your scene looks like) set the direction of the npc
something like:
local pos = game.CurrentCharacter.Position
if pos.x >= 900 then
Characters["npc"].Direction = 90
elseif pos.x >= 400 then
Characters["npc"].Direction = 0
else
Characters["npc"].Direction = 180
end
I think 0 is down, 90 right, and so on... you would have to check if that is accurate.
or... you could use action areas. When the pc enters an area set the alignment of the npc accordingly.