The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →To enter the Basement in Blue Prince, get the Basement Key from the Antechamber, then unlock a Basement door beneath either the Foundation elevator or the Grounds Fountain. The Foundation route requires lowering its elevator from an adjacent room; the Fountain route requires draining the water with the Pump Room. This guide gives the full, spoiler-forward steps.
Get the Basement Key in the Antechamber
- Reach the Antechamber. It appears at the top of the house blueprint, and you must open one of its entrances to get inside.
- Take the Basement Key from the pedestal. The key is available there during a run. If you do not store it, it is lost when the day ends, so plan to use it before then or preserve it using your available storage.
The Antechamber note says, “To continue up, you must go down.” It points toward the route to the Basement, but you still need the key and one of the entrances below. BluePrinceWiki’s walkthrough reproduces the note and describes the key’s location.
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Choose a Basement entrance
Both direct entrances require the Basement Key, but their setup differs. The Foundation entrance uses an elevator; the Fountain entrance is underwater until you drain it through the Pump Room. Each leads to a different side of the Reservoir.
| Route | What you need | Access point |
|---|---|---|
| Foundation | Basement Key; an adjacent drafted room with a doorway facing the Foundation’s back wall | Locked door below the elevator |
| Grounds Fountain | Basement Key; Pool Room and Pump Room access to lower the water | Locked door at the drained Fountain’s bottom |
Foundation route: lower the elevator
- Draft the Foundation. Its elevator cannot be used until you lower it.
- Find the Foundation’s back wall—the wall without doors. Room orientation varies with placement, so do not rely on a fixed compass direction.
- Draft a room next to that wall with a doorway in the shared wall. Go through the doorway to reach the crank or lever mechanism, then operate it to lower the elevator.
- Return to the Foundation, ride the elevator down, and use the Basement Key on the locked door.
After entering by this route, you will encounter a cart puzzle. Move the carts to reach a switch and connect onward to the Reservoir. Gameranx’s guide describes this continuation as well as the elevator route.
#1 Best Overall
- DRAFTING YOUR JOURNEY - Upon reaching a closed door in Mt. Holly, you decide what room appears behind it and each decision shapes your path as you navigate through the manor. Every door can reveal new and exciting chambers that contain their own unique challenges and secrets. But be careful how you draft, for each day the manor’s floor plan resets and the rooms you saw today may not be the same rooms you see tomorrow.
- EVERY STEP COUNTS - Your progress each day is shaped by the rooms you select to draft and the tools you find within them. Items in the game can be used in a number of creative ways to fuel your exploration deeper into the house, allowing you to adopt unique strategies to combat the challenges that each day brings.
- A HISTORY IN THE MAKING - As the heir of Mt. Holly, you have been tasked to explore its shifting halls in search of Room 46. Yet as your journey takes you further into the mansion’s depths, you start to discover that there is more lurking under the surface than a missing room. Investigate a past woven with the threads of blackmail, political intrigue, and the mysterious disappearance of a local children’s book author.
- DAY ONE EDITION BONUSES - Pack-in bonuses include 18” x 12” fold-out poster of the magnificent Mt. Holly Manor and a download code for the official game soundtrack.
Fountain route: drain the water
- Draft a Pool Room so the Pump Room can enter the available room roster.
- Draft the Pump Room, then use it to lower the water level until the Grounds Fountain is drained.
- Go down to the bottom of the Fountain and unlock the door with the Basement Key.
This entrance reaches the opposite side of the Reservoir from the Foundation route. The water level remains where you set it until you adjust it again in the Pump Room.
What stays unlocked—and what the Basement Key opens
Both guides report that a Basement Key door remains unlocked after you open it. You do not need to spend another key to reuse that same entrance. The key opens the two direct doors described above; other routes into the wider Underground involve different prerequisites and should not be confused with either Basement Key door.
Rank #2
- The physical edition will include a fold-out poster of the magnificent Mt. Holly Manor
- Additionally, all pre-orders will include a download code for the official game soundtrack. This code will be included on a voucher inside the game pack for all D1 orders
- DRAFTING YOUR JOURNEY - Upon reaching a closed door in Mt. Holly, you decide what room appears behind it and each decision shapes your path as you navigate through the manor. Every door can reveal new and exciting chambers that contain their own unique challenges and secrets
- EVERY STEP COUNTS - Your progress each day is shaped by the rooms you select to draft and the tools you find within them. Items in the game can be used in a number of creative ways to fuel your exploration deeper into the house, allowing you to adopt unique strategies to combat the challenges that each day brings
- A HISTORY IN THE MAKING - As the heir of Mt. Holly, you have been tasked to explore its shifting halls in search of Room 46. Yet as your journey takes you further into the mansion’s depths, you start to discover that there is more lurking under the surface than a missing room
Other ways into the wider Underground
If you are looking for access to the Underground generally, rather than specifically the Basement room, these routes may be relevant. They take more setup and are not substitutes for the direct key doors.
- Power Hammer: Make it in a Workshop using a Sledgehammer, Broken Lever, and Power Pack, then use it on blocked passages on the Grounds to reach a Mine Shaft and the Basement.
- Tomb: The Tomb is a West Gate outer room; solving its statue puzzle opens another route.
- Precipice: Open the Precipice and light the candle stands in its Underground Sigil Room to create a permanent shortcut, as described by Gameranx.
Guide-reported mechanics above come from Gameranx’s April 21, 2025 guide and BluePrinceWiki’s Room 46 walkthrough, updated in November 2025. The routes described here reflect those guides; later game updates could change details.
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Quick Recap
Rank #4
- Royal prince life simulation
- Explore palace and kingdom areas
- Training, missions, and daily tasks
- Fun mini games and challenges
- Ride horses and unlock new skills
Rank #3
- Brand new. UK Import PAL version. Game in English. UK PSN account may be required for any online features.
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