Resident Evil 9 The Girl Monster Final Boss Guide: Water Treatment Facility Power Switches & Sunligh

The Girl Monster final confrontation in Resident Evil 9 traps dozens of players in an endless loop at the Water Treatment Facility, where her invincibility to bullets and relentless pursuit force you to waste all healing items while desperately searching for the three power switches hidden in the dark corners of the warehouse. If you are tired of dying to her claws while fumbling with the canopy controls, this guide breaks down the exact switch activation sequence, spotlight positioning tricks, and final execution method needed to expose her to sunlight and end this nightmare with one clean shot.

New Player Essentials: New players often waste all ammo trying to shoot her directly, which does zero damage. She is invincible until the final phase. Your only weapons here are light and evasion. Carry the Requiem for emergency stuns and at least two Molotov cocktails to create breathing room. Memorize the three power switch locations before pulling any levers. Never attempt to activate a switch without first stunning her with the nearby spotlight. Time is critical here, hesitation gets you cornered and killed.

Table of Contents

1. Pre-Battle Setup and Supply Check

2. Canopy Controls and Lower Level Access

3. Three Power Switches Strategy

4. Final Execution in Sunlight

1. Pre-Battle Setup and Supply Check

After completing Leon's sniper sequence, proceed to the Water Treatment Facility. Enter the Supply Warehouse and locate the typewriter save point immediately. Drop Emily here to keep her safe during the fight.

Grab the file labeled Canopy Operation Manual from the table. This document hints at the light-based weakness you will exploit later.

Mandatory Gear: Equip the Requiem before descending. This is your emergency brake when she corners you. If you left it in storage, go back and get it now or you will not survive the lower level.

2. Canopy Controls and Lower Level Access

Attempt to operate the canopy opening device on the upper level. The system will fail because the facility lacks power. You need to restore electricity to three separate sectors.

Locate the ladder next to the elevator and descend to the lower level. The three power switches reside in different sections down here, each guarded by the Girl Monster.

3. Three Power Switches Strategy

The Girl Monster will hunt you constantly while you work. Do not engage her with gunfire. Bullets only waste resources and she regenerates instantly. Focus entirely on evasion and switch activation.

Emergency Stuns: When she blocks your path and escape is impossible, toss a Molotov cocktail or fire a Requiem round to freeze her temporarily. This buys you five seconds to sprint past her. Use these items sparingly, you need them for the final phase.

Switch Locations and Spotlight Tactics:

1. Storage Area Switch: Located near the supply crates. Activate the spotlight positioned beside the switch console first. The beam freezes her in place. While she struggles against the light, sprint to the panel and hit the switch. The area illuminates and becomes temporarily safe.

2. Chemical Treatment Room Switch: Another spotlight guards this location. Same tactic, freeze her with light, then activate. Do not linger after the lights come up, she breaks free after thirty seconds.

3. Operations Control Room Switch: This panel lacks a control lever. You need to detour to the nearby Archives Room and grab the Crank Handle Type Three.

Return to the Operations Room and insert the crank. Activate the final switch to complete the circuit.

4. Final Execution in Sunlight

With all three systems online, ride the elevator back to the upper level. The canopy controls now have power, but the Girl Monster will spawn immediately to stop you from using them.

Critical Sequence: Do not run straight to the console. She will intercept and kill you mid-animation. Instead, locate the spotlight positioned next to the canopy device. Activate it first to pin her in place.

While she writhes in the beam, rush to the canopy controls and hit the open button. The roof retracts and direct sunlight floods the chamber. She screams and collapses, her skin burning.

Draw any firearm and fire one shot into her exposed body. She disintegrates instantly. The fight is over.

Key Takeaways:

1. Gunfire does zero damage until the sunlight phase. Do not waste bullets.

2. Activate spotlights first, then hit switches while she is stunned.

3. The Archives Room crank is mandatory for the third switch. Do not skip it.

4. Save Molotovs and Requiem ammo for emergencies only.

5. In the final phase, spotlight her first, then open the canopy immediately.

6. One bullet in sunlight kills her. No need to empty your clip.