Holy Mission is a Tale of Baghdad in Assassin’s Creed Mirage.
Your objective is to help a monk identify the correct grave and later defeat the soldiers.
Here’s a walkthrough and guide of Holy Mission in AC Mirage.
To begin the quest, go to the Tale of Baghdad icon at the northeast part of Harbiyah. The location is shown in the map below.
You’ll meet a monk here.
Help identify the correct grave
Use eagle vision to find a grave that belongs to a person who is worthy to be revered. You will see a few tombstones that are lit in orange.
The correct grave is further away.
Defeat the soldiers
After identifying the grave, three soldiers will show up. Defeat them all.
The quest completes here.