Crag's plan is a paper note in the Fallout 4 add-on Nuka-World.
Location
The letter can be found on the corpse of a dead super mutant named Crag, located in the mirelurk part of the Gauntlet, floating in the water.
Transcript
Crag's Master Plan
1. Find Raider play park
2. CRUSH Raiders
3. Make best meat bag
4. Take stuff
5. WIN