A Delicate Alliance is a main quest in Assassin’s Creed Mirage.
Your objective is to regroup with Ali at a watermill on the northern outskirts.
Here’s a walkthrough and guide of A Delicate Alliance in AC Mirage.
Decrease your notoriety
The quest begins after you escaped from the prison, so you’ll most likely need to decrease your notoriety.
You can remove wanted posters to do so which is the easiest way.
Regroup with Ali
Once you’re no longer wanted, regroup with Ali at the watermill on the northern outskirts as shown in the map below.
You’ll see Ali with his group. Speak to him.
You’ll also meet Roshan in the cutscene. The quest ends here.