More dragon riding in the name of the Bright Lord- this time in defense of the fortress. You goal is to stop the invaders, with bonus goals for staying within the time limit and freeing three captive drakes. The hardest wave of invaders is also the first- the caragor riders. They're fast, and easiest to get them when they're clumped up together. The very moment you have control of your drake, immediately dive down and go into aim mode so you can torch the vermin.
You should be able to get most of them here. Pop off any nearby stragglers, then turn around to see if any groups made it pasts you entirely. If so, head them off (they'll probably be heading to the inner gate, but just follow the yellow markers).
Note that riders who have abandoned their caragor are still a threat- they still have their markers,and should hunted down just the same. Once the first wave of riders is downed, take a moment to fulfull your second special ojective and free the trapped drakes. This is as simple as breathing fire on them. The usual drake indicator marks them on your map.
They'll actually help you mop up the new riders, and other threats
About halfway through the siege, a graug appears. Next to the nimble riders, he's easy prey- just give him a full blast of dragonfire- if the freed drakes don't get him first.
When he's been sufficiently incinerated, the mission ends.