FFXII - Walkthrough - Barheim Passage
Save your game. Outfit yourself with whatever you want/need from the Burrogh. Go back up the stairs and approach the Power Relay... nothing happens. Speak to the Burrogh. Go back up to the Power Relay and try again - the charge is now on and at 100%. Press the Gate Switchboard (beside the Burrogh) to open the gate and proceed onward.
Take out the mimic draining the energy, and then the others. Don't lollygaggle in this dungeon, or the energy may just get dranied entirely...
The next mimic is draining energy down in the southeast corner of Op Sector 29 - run down the stairs and take him out.
Move on to the next area. A battery mimic is brazenly feeding on an energy conduit right in front of you - go teach it a lesson.
When the corridor splits in two, head right - you may notice a mimic feeding on yet another energy conduit. Take him out. Head back up to the divergence point, and now go left.
Another divergence point - go left to stop another energy-sucking mimic, then double back and head right. Note that your Location Map indicates where Damaged Power Conduits are located, in case you're confused.
A bit further forward and you'll reach another divergence point, the third so far in the Great Eastern Passage; the path you were walking on ventured southwest; at this junction, you can proceed southwest, or venture North to a dead end. Take this Northern path, because there's an Urn at the end of it with the map for the Barheim Passage, thus giving you the layout of the dungeon and saving me the effort of explaining things like this!
Continue down the Great Eastern Passage; secure the last visible energy conduit. Head West to Op Sector 36 and secure two more energy conduits.
Down to Special Op Sector 3; more energy conduits, more mimics to take out. Flans begin to appear as well - don't forget they're weak to Fire, if you got it. There's a large gate, but you can't open it now - you need to go to the northwest part of Op Sector 37.
Op Sector 37, two more conduits to clear and as I just mentioned, the Gate Switchboard to open the gate leading to the North-South Junction of Barheim Passage. Go there.
Cutscenes, and a save point. Save your game, and proceed forward.
In the Great Central Passage, treasures now stand a chance of being mimics in disguise, so don't get caught off guard. Take out the mimic at the energy conduit, and move on.
The Zeviah Subterrane - 3 conduits in total, so take care of business. I strongly recommend heading to the southwest area and picking up a rather valuable weapon - the Oaken Pole, which should be the strongest weapon you have at this point.
Terminus No. 4 Adjunct - big boss fight coming up! Save your game. If you think you need anything else, head back to the start, sell whatever loot you've acquired, and buy what you think you need. It's a pretty long way back though, so you might as well give the boss a shot...
MIMIC QUEEN
Steal: Knot of Rust
Attacks: Breath of Life, Spawn (spawns mimic), Shockstorm (Big dmg all in range), Ground Shaker (Same)
Advice: You'll either find this easy or tough; I mean, I had a lot of trouble with this on my first playthrough, but pretty much none this time! Just watch out for Shockstorm. Make sure your gambits are set appropriately so everyone focuses on the Mimic Queen, don't worry about the little mimics. You'll either find this very easy or very hard, depending on who/how strongly Mimic Queen's range attacks hit you for.
Once the battle's over, you'll have a quick cutscene and you'll be shown a complete map of the Estersand. Of course, you don't have access to this map, and as soon as you exit this screen it'll all be lost, so take a look at it while you have the chance.
You have three options: head South to Rabanastre, head north to the teleport crystal at the village on the riverbank, or head to Nalbina Fortress. The arrow to the southeast of where you are, pointing northwards, leads you to Nalbina Fortress, where you can purchase some new goods (and it has a teleporting crystal). The arrow pointing southwest, to the northeast of Rabanastre, leads you to the Giza Plains. You can't go beyond the village with the teleport crystal at this point, so don't worry about what's up there - all in due time.
Save your game, pick which path you want to go to, and head off.
Back in Rabanastre - everybody leaves the party! Save your game, and speak to Hurdy; the Moogling is now available, which lets you teleport to various areas of Rabanastre free of charge. Definitely a time saver!
First order of business: Clan Centurio. Montblanc will give you 550 gil for the three previous boss fights. Now go around town and buy whatever you feel like, and then go to Migelo's.
Following Kytes request, go to see Old Dalan in Lowtown; entering via Southgate is quickest.
Dalan gives you a sword and tells you to deliver it; your Location Map clearly shows where to go. Head there. Speak to the "Rabanastran" sitting on the crate.
More cutscenes; Basch (finally) joins your party. You next quest is to find Balthier; he's chilling at The Sandsea, so go there & speak to him. Balthier and Fran rejoin your party. Next stop: the Lhusu Mines in Bhujerba. Bhujerba has plenty of shops, so don't feel the need to stock up in Rabanastre.
Do some hunts if you feel like it; once you're done, Balthier is waiting for you at the Aerodrome (red X on your location map - beside the Westgate moogling/save crystal). Balthier is standing near the rear of the Aerodrome; speak to him... note that you won't be in Rabanastre for a while, so make sure you're good to go.