Finishing the Supermarket Journey quest will trigger this one. Head back through the sewers to City Hall. Once you get to City Hall complete the Big Daddy Where Are You? side quest to get the key from the dead mayor's body. Once you head back into the sewers, try to run past the enemies because there are so many of them. The mission will end when you get back to the church. Talk to mother Helen to start the next main quest Lady in Trouble.
Pride Shotgun Mod - Once you're back to City Hall and get to the second staircase, head down and there is a breakable door. There's a bunch of enemies including a ram, once you get past them the blueprint is in the lower area that you walked around on the floor above in a broken dresser.
Magic Wand Mod - After you kill the zombie mayor in his office, you'll find it sitting on his desk.