In my mod the player aquires a follower by freeing him from a jail cell. When you talk to him he gives you a fake key and tells you to swap it for the real one, which is in the possession of another NPC. I need it to only be able to be swapped with the fake key, nothing else. How do I do this?

And I need a follower script. I know how to do one but I dont know how to start it with the flags and whatever after I let him out.

thanks

Script it. Since keys can have a script, place a script on your fake key. Have it check to see if the player has it in his possesion and if the palyer is within proximity of the other key/NPC. Then have it pop up a messagebox with options to swap the key or not. If the player chooses to swap keys, swap them via the script. You may also want to put a delay on the script such that after the message box pops up, there is a delay before another one will pop up. I'm sure there are other ways, this is just one idea.

As for a follower script, just look at any of the vanilla follwers and modify there script for your follower.