With this whistle you can call down a Wintergarde gryphon. Mount the creature and head towards the ruins of Wintergarde Village, now known as the Carrion Fields, southeast of here. Once at the fields, keep your eyes peeled for helpless Wintergarde villagers. When you spot one, fly low and use the gryphon to pick them up. Return the rescued villager here, to the gryphon station.
There are Scourge all over the place so you'll need to keep your wits about you, hero. Good luck!
Progress
Hurry, <name>! You need to save the helpless villagers!
Completion
Outstanding work, <name>! We can get this keep back into working order now with the return of our citizens.
Notes
Use the whistle. Get on the gryphon. Fly to the fields below Naxxramas. Get close to the ground in front of a perpetually fleeing villager, stop moving, then hit #1 (Rescue villager). Once the villager is on your mount, fly back to the gryphon stand and hit 2 (Release villager) to drop him or her off. Repeat.
You can only pick up and drop off villagers when you are not moving. You can hover, but not have forward speed.
If you try to fly outside Wintergarde Keep or Carrion Fields, you will get a warning that the Gryphon will drop you. Fortunately, you will be provided with a parachute. (The buff tooltip mentions Wintergarde Mine, but this is an error.) Wintergarde Mausoleum is not considered part of the acceptable area, despite it being wholly contained by the Carrion Fields, and will dismount you.
The villagers run around quite fast. Using the Soar action (button 3) will help you catch up. It gives a 350% speed increase, lasts 8 seconds and has a cooldown of 8 seconds, so you can effectively use it continuously.
If you dismount from your Gryphon while you are carrying a villager, the villager will disappear.
You might notice that your villagers head for the inn; when you finish the quest, the innkeeper and other NPCs offering services will be phased in for you, they being the people you rescued. Additionally, the Carrion Fields will be deserted of fleeing villagers, having been airlifted to safety. A wanted poster offering quests will also spawn inside the inn.
Quest progression
[72] The Lost Courier (optional, starts in Borean Tundra, leads to Stars' Rest)
There is a reference to The Terminator when picking up a villager, there is a chance that your character will automatically say "Come with me if you want to live."