Once you complete the normal storyline and beat the final boss, Corbenik, of the cursed wave you will have an opportunity to continue playing the dot hack quarantine game once the credits have concluded. One of the missions that appear will be one where you will be able to journey with Elk to resurrect Mia.
This mission is pretty straightforward with the over world and dungeon except for the fact that the dungeon is 15 floors deep and the majority of enemies are data bugs. The major challenge here is getting through the dungeon without getting a game over due to too much data draining.
Some words of advice are to find a low level dungeon before doing this mission and getting your infection statues well into the blue area. The next thing you will want to do is purchase at least 16 fair orbs so that you can map out each floor of the dungeon and the over world. This will help you avoid unnecessary fights with enemies.
The first thing you will need to do is use a fairy orb to reveal the enemies on the over world area. Once they appear plot a path to the dungeon entrance avoiding all the enemy encounters that you can. Once in the dungeon, start out each floor with a fairy orb to see how the floor and the enemy locations. Once you can see all the rooms and enemies, plot the shortest path possible, the path with the least amount of enemy battles, to the “down” staircase, leading to the next floor. I strongly advise against trying to get off the path treasures, these temptations usually do more harm than good.
The battle with the dawn wanderer and temptress lover isn’t too bad. I would advise having your members keep attacking with their skills and magic and use kite as the healer for the party. Once you defeat both forms you will get to see Mia’s return and also the privilege of having her as one of your characters again.