The Nazgûl entering the Shire seemed to cause an increase in the Blackwold brigand troubles in Bree-land, and so Amdir was sent to Archet to investigate. Here he attended to the problem of some missing Hobbits, and got himself deep into some nasty business because of it.
He should be familiar to those whose adventure began in Archet, and he is featured in both the Hobbit and Man starting instances, as well as the Epic prologue quest for Bree-land. Without giving too much away, we'll say that he is very involved in this storyline. View the lorebook entry to see some of the quests he's involved with, and the map of his location.