City Newcomer

Talk to Marvin after establishing your new base of operations. Head to the harbor cafe and attempt to open the gate. Enter the shop beside it and search the counter to find the key.

Head south to the city then enter the workshop to the right (west). Inside, you'll find various materials, a quest item (Keepsake Photo) and a Short-Circuit Mod on the top shelf.

Continue south and be careful of the flooded street since there's a lot of drowners there. There's also a quest item (Message in a Bottle) beside the red bag by the stairs outside the workshop. It will say something about someone trapped on the roof behind the church. We will check it later on.

Continue to the flooded town center where there are a dangerous number of drowners among the bloated dead. It will be a good idea to lob an explosive or two in the group of corpses and see how many of them reanimates and attack you. Go upstairs to the next area and you'll find a Ram with several walkers. I suggest taking the high ground and kill the walkers from there then go back to the ground and lure it to a wall. Wait for it to start its charge then quickly move out of the way. Once it hits the wall, continue attacking its exposed back to deal critical damage.

After dealing with the ram, approach the cinema if you haven't done so yet to have your quest updated. Now you have to find an alternate route by going around to the east. Go to the ramp by the flooded street and you'll find a ladder. Go up and find the back entrance. Enter it to complete the quest.