Chapter 2
Hawkins Square
Side Quest: Gearing Up 2: The Re-gearing
Includes: Rats in the Walls
Near the Pan-O-Rama pizza joint on left side of map, talk to Fanatic who gives you a quest to bring him a Flashlight. Go to Hawkins Hardware and talk to Joey. He asks you to solve his Rat problem.
Clear all the rats from the back rooms of the Hardware store. Get Joey to unlock another door. Clear that room. Don't forget to use Lucas' bomb on boulders to reveal a chest with loot in the back corner. Talk to Joey again to complete the quest. Joey will now sell you stuff, including the flashlight you need for the Fanatic, who gives you a Trinket for your troubles.
You might be able to do this without talking to the Fanatic first. But I included his quest because of the reward he gives.