How to Unlock the Red Door in the Underpass in Blue Prince

Blue Prince is a game filled with secrets, hidden passages, and intricate puzzles. One of the most intriguing mysteries is the Red Door located in the Underpass, which cannot be opened from the underground itself. Instead, players must manipulate the environment inside the manor to unlock it.
In this guide, we’ll break down exactly how to find the Red Door, what prerequisites are needed to access it, and what lies beyond it once opened.

Step 1: Gaining Access to the Basement

Before you can even think about reaching the Red Door, you must first unlock the Basement. Here’s how:

Find the Basement Key – Located in the Antechamber, this key is essential for accessing the underground areas.

Unlock the Basement – Once you have the key, head to the Basement entrance (location varies depending on your manor’s layout) and unlock it.

Step 2: Solving the Cog Puzzle in the Basement

Inside the Basement, you’ll encounter three locked doors and a giant cog mechanism. Solving this puzzle is crucial for progressing toward the Red Door.

Unlock the Three Basement Doors – Search for keys or mechanisms to open these doors, granting access to different tunnels.

Interact with the Giant Cog – This rotating platform acts as a bridge between tunnels.

• Turn the cog so that it aligns with the blue tunnel on the opposite side of the room.
• Carefully walk across the cog to reach the tunnel.

This path will eventually lead you deeper into the Underpass, where the Red Door is located.

Step 3: Locating the Red Door in the Underpass

After navigating the Basement’s tunnels, you’ll find yourself in the Underpass, a network of underground pathways.

• Follow the tunnel leading to the final lever (used for another puzzle).
• Along the way, you’ll spot the Red Door—but it’s locked, and there’s no visible way to open it from here.

This means you’ll need to return to the manor and manipulate another part of the house to unlock it.

Step 4: Unlocking the Red Door via the Boiler Room

To open the Red Door, you must activate a mechanism in the Boiler Room. Here’s how:

Draft Floorplans Until You Find the Boiler Room – Since Blue Prince features a semi-randomized manor layout, you may need to keep generating floorplans until the Boiler Room appears.

Rotate the Three-Pronged Steam Pipe – Inside the Boiler Room, you’ll find a pipe system.

• Adjust the pipes until the red box on the wall lights up, indicating that steam is flowing correctly.
• This action unlocks the Red Door in the Underpass.

Donate: buy me a coffee

Important Note:

• Once the Boiler Room mechanism is activated, you must manually return to the Underpass.
• Ensure you have enough steps (movement points) to make the trip, as backtracking can be time-consuming.

Step 5: Entering the Red Door & Discovering Its Secrets

After unlocking the Red Door, simply approach it, and it will open automatically. Inside, you’ll find:

• A New Puzzle Box – Another brain-teasing challenge to solve.
• Additional Lore – Clues about the manor’s history and the enigmatic Blue Prince.
• A Blue Prince Safe with a Red Envelope – Potentially containing valuable items or story revelations.

Final Tips for Success

• Plan Your Route – Since unlocking the Red Door requires multiple trips between the manor and Underpass, manage your steps wisely.
• Explore Thoroughly – The Basement and Underpass hold many secrets; don’t rush past potential clues.
• Experiment with Drafting Rooms – If the Boiler Room doesn’t appear immediately, keep trying different floorplans.

Conclusion

The Red Door in Blue Prince is a perfect example of the game’s layered puzzles, requiring playersto think both spatially and logically. By carefully navigating theBasement, solving the cog puzzle, and manipulating the Boiler Room’ssteam pipes, you can unlock this mysterious passage and uncover evendeeper secrets beneath the manor.

Happy exploring—and may your steps lead you to the truth hidden behind the Red Door!

Donate: buy me a coffee

---

Other Articles Related

How To Use Treasure Map in Blue Prince
Learn how to effectively use the Treasure Map in Blue Prince to uncover hidden secrets and valuable loot. Master navigation and maximize your rewards with our step-by-step guide!
How To Use Gear Wrench in Blue Prince
Learn how to use a GearWrench effectively with Blue Prince’sexpert guide. Discover tips, techniques, and best practices formaximizing your wrench’s performance. Read now!
Where to find All Upgrade Disks In Blue Prince
all upgrade disk locations for Blue Prince in our comprehensive guide. Maximize your gameplay and enhance your experience
How to Get Still Water in Blue Prince
Discover the secrets of  Blue Prince  and learn how to achieve still water for your aquatic paradise.
How To Start a Laboratory Experiment in Blue Prince
Unlock the secrets of initiating a laboratory experiment in Blue Prince. Explore guidelines, best practices
How To Unlock Her Ladyship’s Chamber Diary in Blue Prince
Discover the secrets of  Blue Prince: Unlock Her Ladyship’s Chamber Diary.  Dive into a captivating tale
How To Redraw Rooms in Blue Prince
Discover expert tips on how to effectively redraw rooms in blueprints. Transform your space with our step-by-step guide!
How To Use Moon Pendant in Blue Prince
Discover the enchanting ways to style a moon pendant in blue prince. Elevate your fashion with our expert tips and creative ideas!
How To Use Broken Lever in Blue Prince
Learn how to effectively use the broken lever in Blue Prince with our step-by-step guide.
How To Find the Tunnel Floorplan in Blue Prince
Discover how to locate the tunnel floorplan in Blue Prince with our step-by-step guide. Simplify your search today!
How To Get Bloodwood Sap in RuneScape Dragonwilds
Discover the ultimate guide on how to get Bloodwood Sap in RuneScape Dragonwilds.
How to Solve the Closed Exhibit Puzzle Box in Blue Prince
Unlock the secrets of the Closed Exhibit Puzzle Box in Blue Prince with our step-by-step guide.
How to Get Sacred Water in Path of Exile 2
Discover the ultimate guide on how to obtain Sacred Water in Path of Exile 2. Unlock secrets and enhance your gameplay today!
How to Get More Stamina in Oblivion Remastered
Discover effective tips and strategies to boost your stamina in Oblivion Remastered.
How To Join The Thieves Guild in Oblivion Remastered
 Discover the ultimate guide on how to join the Thieves Guild in Oblivion Remastered.