Suikoden III Geddoe Chapter 3 True Lightning
Brass Castle
Surely you built up a ton of ability points at Mount Senai, so use them up at the Bujutsu Teacher since Geddoe can enter the center area now. West, and Aila will try to take out Percival.
Vinay Del Zexay
Check out the rarities at the Item and Armor shop when you get here. Then, rest at the Inn. Geddoe meets with someone, who says to go to the North Cave. You can get Script #2 from the kid at the Inn if you have not yet. Leave VDZ and Ace will come running after the rest of the group.
North Cavern
Duke, Elaine, Gau and Nicolas confront you near the end of North Cavern. It is duel time with Duke - he is not too tricky, plus he defended the first 3 turns in a row. After he is bested, Duke and friends turn around and let you go.
Up ahead is no treasure boss, and no person actually. Go to the far north to look outside, then Salome and Louis come by. They tell of a possible Harmonian invasion, and then Salome says to aid the castle across the lake (Budehuc Castle).
Return back in the North Cavern, and go to the end for the StoneGolem. Stone Golem has some powerful physical attacks, and has a brutal defense. Lightning Rune magic will be your best bet here, and it will likely take a while unless you have someone else like Queen casting. 100,000 Potch, Premier Helm, Premier Casque, Custom Leather, Robe of Mist, Ninja Suit, Engraved Gauntlet, Herb Seeds and a ? Statue.
Rest up and save at Vinay Del Zexay, then go to Budehuc Castle.
Lake Castle / Budehuc
As you enter, you will see all the scenes from Thomas Chapter 2. Check out the library at Budehuc when you get a minute, and for some odd reason Eike knows about Captain Geddoe.
Geddoe's party goes down the stairs and finds a place to sleep for the night. At night, Captain Geddoe shows Joker the True Lightning Rune.
Next day, watch as Leo and Percival leave. The councilor sends in some Zexens, but your party ambushes the back end. Another set to take out inside the castle.
After saving the day, Geddoe says it is time to go to the Flame Champion's Hideaway. First, go to Caleria. It is a long ways away, but you want to talk to the merchant outside the Armor / Blacksmith shop, for a Copper Hammer. You can sharpen weapons to level 12 now.
Budehuc Castle
Make the long walk back to Budehuc. It is worth it, to get everyone's weapons to level 12.
Flame Champion's Hideaway
The FlameChampHdaway is past Kuput Forest. Geddoe can't visit Chisha unfortunately, but shouldn't need to.
Take the northwest path until you get to the room with the teleport. Take the northeast path in this one, and then northwest again to get to a save point and the Azzodess boss. Having a Yellow Scarf on your healer Joker would be nice. This way Azzodess' special move doesn't completely screw you over. The True Lightning Rune should be able to carry you through this battle anyway. 120,000 potch, Wind Rune, Stone of Evasion, New Helm, and a ? Painting are your rewards.
Leave to Duck Village to rest / Save, if you want. Or else, just hit that teleport in FlameChampHdaway with Geddoe. Geddoe Chapter 3 ends as he is the last to reach Sana.