When you enter Updaam during the afternoon time in Deathloop, you’re going to receive a call from an angry Eternalist. They’ve become tired of how things are going and want to give you a hand. They’ve left a present for you at the Dorsey Manor that you can pick up.
When you want to receive this quest, all you have to do is arrive at Updaam during the afternoon time slot. You should receive it immediately when you enter the area. You’ll then want to go to your Arsenal Leads menu and make sure to activate it. From there, you’ll receive a waypoint to the Dorsey Manor. When you arrive, there will be a massive present right in the middle of the area. Not suspicious whatsoever.
After interacting with the present, it turns out to be a trap. Multiple Eternalists spring from their locations and attempt to take you out. The primary one you want to eliminate is the one in the bakery. They’re going to have a special sniper rifle, the Sepulchra Breteira. When you loot it, you’ll want to make sure to have enough Residuum to take it back to the tunnels and infuse it, allowing you to take it with you on every loop.
While this is a short quest, it’s worthwhile to finish and acquire the Sepulchra Breteira sniper rifle.