Power Play

Power Play is a quest and achievement/trophy in the Fallout 4 add-on Nuka-World.

Quick walkthrough
After setting up three raider outposts, a quest pops up telling you to talk to Shank. He sends you back to Nuka-World with news of a revolt by the leader of the gang to whom you gave the least land. You must meet with the other leaders to retake the Nuka-World power plant, and after a small chat and you storm the plant with the other two. Fight your way to the roof where you kill the rogue leader. You then go to the power control room and flip the switch to bring power back to Nuka-World in full.

Detailed walkthrough
The quest begins upon establishing the third raider outpost in the Commonwealth. The first step is returning to speak to Shank, whether he has been sent to the Commonwealth or remains in Nuka-World. He reveals that, depending on how the previous eight territories were doled out (five theme parks, three Commonwealth outposts), the gang that got the fewest territories has rebelled against the Overboss's decisions, taking control of the Nuka-World power plant.

Meet with the other bosses outside the power plant. No matter what dialogue choices are selected, the end result is that the traitorous gang and its leadership must die. The bosses join in the assault on the power plant, fighting through the traitorous gang's forces (who fight like ordinary raiders) and some feral ghouls.

The boss makes their last stand on the roof outside. After killing them, the player takes the control room key off the boss's corpse and proceeds to turn on the main power to Nuka-World. Fireworks erupt over the parks as the lights come back on. Talk to Gage to complete the quest and bring the main story of Nuka-World to an end.