The Return is a main quest available in Assassin’s Creed Mirage.
Your objective is to fight your way out with Ali and return to the Bureau.
Here’s a walkthrough and guide of The Return in AC Mirage.
Fight your way out with Ali
This quest begins after you assassinate the Warlock. You’ll now need to fight your way through the soldiers with Ali and the rebels.
Keep fighting all the way to the main entrance.
Then, follow Ali and the rebels out of the Garrison.
Speak to Fuladh
Go back to the Bureau to speak to Fuladh. The location is marked in the map.
The quest ends here. You’ll earn the Disciple rank and some items.