How can I make it so that an event will happen, when an NPC is pushed onto a certain tile?

In a plotscript do...

script,plotscript,begin
if ((NPC X (The NPC Number))==The X Tile)
 then (
 if ((NPC Y (The NPC Number))==Put the Y tile here)
  then (
  Put whatever, you want to happen when NPC is on that spot, here
  )
 )
end

This is great if you want a button, or something, and you have to push a NPC onto the button, for a door to open up.

If this is the case, simply make it set tag when it is on the spot, and then activate this script by a text box somewhere, and if the text box senses the tag is on make it go to the next text box that lets you advance further into the game.