The ultimate challenge in the Fortnite Chapter 2 "Forged in Slurp" mission is to carefully examine this week's loading screen. This is where you will find the clue that will lead you to the famous hidden 'R'.
As for the previous season, you will have to wait until you unlock the loading screen via temporary missions to hope to get your hands on the famous letter.
Map
To find this famous 'R', you will have to sail to the northeast part of the big Slurpy Swamp factory. The 'R' is located under the iron structure that supports the pipeline flowing into the swamp.
The Team Rumble mode is recommended to complete this challenge, since it allows you to come back to life quickly!
