You get that as part of completing "Mind over Matter". For me it started by finding Bellegar's Coin on a corpse on such-and-such Lane. When I found the person looking for that, they gave me an item someone else wanted, and so on in a chain reaction of sorts. Eventually everyone got their item, including the Raccoon Rune for Valeri. You don't need to enter undead areas or dungeons to complete this quest/achievement. Oh, and in case you didn't realize: as the quest name suggests you can only do this by reading minds.
