Halls of Lightning is a dungeon in the World of Warcraft game. The level range for the normal dungeon is 77-80. The instance was released in the Wrath of the Lich King expansion. The dungeon contains 4 bosses. The end boss of Halls of Lightning is Loken.
The Halls of Lightning is one of two dungeons on the rock at the northern most part of Storm Peaks on the continent of Northrend. The entrance is at location coordinates 45, 21. The other dungeon is Halls of Stone. This is also a raid in the middle of the rock but you will need to fly up to reach it called Ulduar.
The first one has you fighting a giant General Bjarngrim who has gathered the support of the Dark Iron Dwarves. He occassionally has an electric force field which can spur on his minions and cause damage to the party. If you can kill him when the electric is on, there's an achievement for you. Bjamgrim done, onto the next boss.
Volkhan greets you at the top of the stairs. Volkhan must be killed before you can go through the door to the next encounter. In the next room, the stone statues will come alive as you pass them so don't say I didn't warn you.
Ionar is a ghostly boss who periodically will set his electric spider onto you. You need to run away from the spider after a short period, the spider will disappear and you'll go back to killing Ionar.
The next bunch of trash are dwarves and giants, you need to be careful so as not to pull all the trash.
Success on the trash will lead to the final confrontation with Loken. The name Loken is a take on the Norse God Loki, the God of Mischief. Every so often, Loken will cause AOE damage, you need to stack on the boss. The further away you are, the more damage he does. There you go, the Halls of Lightning done.