This challenge is part of the Location Domination Overtime Challenges in Fortnite. These challenges will allow you to gain XP to complete your battle pass or unlock golden skins. One of the challenges will require you to catch weapons at Misty Meadows, and this mission is pretty simple.
Map
Once there, take a fishing rod or a harpoon and try to fish a weapon with it. It should also be possible to catch a weapon on the ground with a harpoon. If you want to be more relaxed, you can use the Team Rumble mode.
Original content by Maxime "Biaggi" Ricoveri.
Here's everything you need to know about the new Fortnite Chapter 2 Season 2 Location Domination Overtime challenges and rewards.
