Power Play

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

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.

Multiple reward options
After finishing this quest, the player character will receive perks according to which gangs didn't rebel.
 * Perks
 * If the Operators didn't betray the player character, they will receive the Ace Operator perk.
 * If the Disciples didn't betray the player character, they will receive the Chosen Disciple perk.
 * If the Pack didn't betray the player character, they will receive the Pack Alpha perk.

After defeating the traitorous gang and turning on the power, speaking to the two surviving gang leaders will provide some follow-up dialogue and new weapons to complement the unlocked perks:
 * Weapons
 * Nisha provides a Disciples blade with the Instigating legendary effect, which deals double damage to enemies with full health.
 * Mags provides an Operators sniper rifle with the Relentless legendary effect, which refills Action Points on a critical hit.
 * Mason provides a puncturing rocket baseball bat with the Furious legendary effect, which deals increasing damage for each consecutive hit on the same target.