At least some content in this article is derived from information featured in Harry Potter: Hogwarts Mystery. Spoilers will be present within the article.
|"I show not your face but your heart's desire."|
Jacob's room had a lock on the door with two keyholes, a wooden table in the centre of the room, a conspiracy board, papers stuck to the wall, a wooden cabinet against the wall and a chair with a white sheet over it.
At some point, Merula Snyde and Tulip Karasu discovered the room during their own search for the vaults. After each discovered that the other had been sneaking into the room without their friend's knowledge, Tulip secured the door with a special lock. The lock was resistant to the Unlocking Charm and required two keys, one for each of them, to open. The two had a falling out over the issue and the room remained closed.
In 1986, Jacob's sibling discovered the existence of the room from one of their brother's journals. After unsuccessfully trying to unlock the room on their own, they spoke first to Tulip and then Merula, eventually getting the keys from both girls.
Harry Potter: Hogwarts Mystery (First appearance)