You could use the chase character action part. In an at begin of scene action of the next scene: set the npc to the scene & call another chase character action part.
Leave the execute action on character catch (whatever it's called) empty so that no action is performed when npc reaches character based on radius set. I forget exactly how it works as it's a long time since I looked at that action part.
P.S: it might be a good idea to wrap the set character to scene action part in a:
-- action parts
if character "character_name" is on current scene
else
set x character to x scene
end if
... Ok I'll use chase function but how and where? On main character or npc's actions?
