In all honesty, the main quest, "The Voice" accessible through Bowerstone Industrial, took me less than 45 minutes. In addition to that quest (which unlocks the city of Understone and a new moral choice at the end of the quest), the "Understone Quest Pack" adds a quest at the mercenary camp, "Shooting Range" (bet you can't guess what that is), and a quest in Reaver's old mansion, "The Wheel of Misfortune." I haven't tried out either of those yet. GamesRadar's review sums up my feelings about this DLC so far pretty well.