void main()
{



     object oPC = GetEnteringObject();

        // replace this tag string with the tag string of your NPC.
        object oNPC = GetNearestObjectByTag("secretdoor3");

        {

                // check to make sure NPC isn't already talking to somebody.
                if (!IsInConversation(oNPC)) {

                        // stop whatever we were already doing.
                        AssignCommand(oNPC, ClearAllActions());


                        // start talking to PC.
                        AssignCommand(oNPC, ActionStartConversation(oPC));
                }
        }
}