Item in inventory - I don't want it to be moveable

I’ve made an item that I’ve marked as “plot” that I’ve placed in the inventory of a companion. I don’t want the player to be able to move, drop or sell this item at all. I thought it was just to mark it as “plot” but that didn’t work. The item can still be moved to the player’s inventory in game. How does one do this? Thanks.

Set it as plot and cursed.

Oh? Ok. Then I’ll do that. Thanks for the answer!

You can also use tag scripting for doing this.