Secret Garden Key
The Secret Garden Key or Key to the Secret Garden is a special item in Blue Prince. Although it is a relatively common special key with its destination in the name, the place where the Secret Garden Key must be used is left deliberately unclear.
How to obtain
This item can be found in the following locations.
[Found Floorplan: Lost & Found]
This item can be purchased from the following shops.
- Locksmith — 8
This item can also be obtained from the following sources.
- Trunks
- Dig spots, rarely
- The Dartboard Puzzle in the Billiard Room
- [Garage Spoiler] The trunk of the car in the Garage, after the Upgrade Disk has already been used
Usage
While the Secret Garden Key is held, it will appear as an option in the special key menu while trying to unlock a locked door. However the Secret Garden Key will fail in most cases, with a red message that says "THE KEY DOES NOT FIT".
Spoilers Within
This section contains spoilers for Secret Garden Key usage.
Success when using the Secret Garden Key depends on the position of the door in the house. Only doors leading into the West Wing or East Wing will accept the Secret Garden Key. The wings do not include corners for the sake of drafting, and it cannot be used on a Rank 2 door even if it is somehow locked, meaning the door must lead into an edge tile from Rank 3 to 8. The Secret Garden Key can never be used on a Great Hall side door or a 
[Studio Addition: Vestibule] door, though it can be used on the Great Hall far door if it leads to a valid position.
Using the Secret Garden Key successfully will unlock the door, saving the use of a basic key. The ordinary floorplan drawing process is then entirely skipped to immediately draft the Secret Garden.
Using the Secret Garden Key removes it from the inventory. Unlike the Silver Key and Prism Key, the Secret Garden Key is not returned to the item pool after use, preventing multiple copies of the Secret Garden from being drafted in the same day.
Beyond the Estate
This section contains datamined information. It may contain spoilers for various stages of the game.
When the key is used, a round of 3 draws still occurs as normal; it just gets ignored and a Secret Garden is drafted instead.
This influences effects involving drawing a room (even if not drafted) such as some dares in Dare Mode, the Runback Filter, or some Forced Draws.