Sceptre of Fire
A Bargain Is Struck
After a short dialogue, you have to get four caravans to your keep in the north. This is a straightforward mission. Merely move the caravans towards your keep. Recruit two or three units for Rugnor and send them south at all speed (scouts work well here, provided you are playing on 1.7.x). Use your units to shepherd the caravans, cutting it off from the elves, until it reaches the mountains. Normally, your human allies wipe out the elven attack before your troops can get stuck in, but if you can get some experience, all the better for the next mission. Use this chance to gain some experience for Rugnor in particular.
Because the humans are so effective against the elves, you may be able to simply ignore the caravans and go kill the elvish leader. Remember elves are tough to hit in forest, so concentrate on picking off the ones who venture into the grassland and let the humans take their licks against the dug-in elves.
Closing The Gates
This involves hunting down some trolls and stalling the elves. Firstly, recall and recruit a substantial amount of thunderers and fighters. Move all your guardsmen down towards the three towers, those two glyphs can be easily covered near the end. Move two thunderers down that way as well.
Send Rugnor and one or two fighters and a thunderer down a passage and send the rest of your forces to kill the trolls at the other passage. Once they are dead, close the glyph beside the side entrance. This will close it (I managed to shut a troll whelp outside, who promptly killed two elf scouts over the course of the scenario and managed to level up :D). Leave two behind to hold those glyphs in the passage you picked and repeat for the other passage. Then once you have done that, defend the gate until turn 14 or so, picking up as much experience as possible (try to get Rugnor at least to level 2). Then, pull all your troops back behind the gate (any left outside will automatically die, and those trapped in the door will be squished) and place any soldiers on the two remaining glyphs.
In The Dwarven City
A mere cutscene. Sit and enjoy.
Searching for the Runecrafter