The Old Chateau (Japanese: もりのようかんForest Manor) is an abandoned mansion near the exit of the Eterna Forest. Inside one of its four bedrooms, there is a television, which, if interacted with at night (only after obtaining the National Pokédex in Diamond and Pearl), will initiate a battle with the only obtainable Rotom in the game. Cut and, by extension, the Forest Badge, are required to enter the Old Chateau.
The Old Chateau is a very strange house located deep within the Eterna Forest, near the western entrance, only accessible by HM01 (Cut). The mansion is known to be haunted, scaring many citizens of Eterna City, especially Gardenia, who sometimes appears before it cowering in fear at the urban legends related to it.
Upon entering, the Old Chateau appears to be old and abandoned. The first room encountered is the foyer, which has two flights of stairs both leading to the first floor. Between the foyer's staircases is a door to the dining hall, where a long wooden tables dominates the room. The kitchen area can be accessed on the left side of the table. Just outside of the room stands a strange statue with an ominous aura; the statue "appears as if it is glaring".
On the first floor, left and right of the main room extends a library, where old books are crammed into bookshelves.
There are also four bedrooms that can be accessed to by traveling further up the first floor. In one of the rooms there is a television that is on and displaying a plain, white, flickering screen. The television is inhabited by a wild Rotom, which will come out at night time, and initiate a battle. There is also a portrait in another room; glowing red eyes appear on it that will stare and seem to follow the player.
Sometimes, what seem to be the ghosts of a little girl and a butler appear in a bedroom on the first floor and in the dining hall, respectively.
The little girl appears when the player enters the room next to the bedroom where the ghost "is". She appears to "walk" through the door and is never seen on the other side.
The butler appears to be sitting at the other side of the table in the dinning room. The player walks forward and he starts to "walk" to the left side of the room, leaving the game window. He never appears on the other side. Unlike the little girl, the butler does not use a walking motion. He instead appears to "float" just off the ground.
These two characters cannot be interacted with, which—accompanied with Gardenia's reports that the Chateau is haunted—lends to the theory that they are both ghosts.
Additionally, the picture in the room, in which the ghost of the little girl is visible, the eyes may begin to "blink" and/or follow the player.
Notebook
In Pokémon Platinum, one of the books on the floor in the library is just barely readable. It says:
"It's an old notebook. There's something scrawled in it..."
"Som...hing so pecu...r shou... make off ...ith the mot..."
"The rest of the pages are blank."
It most likely says: "Something so peculiar should make off with the motor".
A colored background means that the Pokémon can be found in this location in the specified game. A white background with a colored letter means that the Pokémon cannot be found here.
The Old Chateau is located in Canalave City in the anime. Here people can make the Old Gateau using the instructions and ingredients found there. It is also run with an automated voice to guide the people visiting the mansion, which also served as a hotel.
In the episode Get Your Rotom Running!, it was abandoned for a while due to electricity problems from a recent thunderstorm. As a result, a Rotom took residence there for a while to play with the people coming in by possessing different appliances.
Trivia
In Pokémon Platinum, it is implied that Charon used to live here, suggesting that he is the owner who abandoned it, especially with his credit for discovering Rotom.
The notebook found in Pokémon Platinum seems to have been written by Charon as it reads the following message if the blanks are filled in:
"Something so peculiar should make off with the motor... "
As the ghosts pass the game window, the player is unable to move.
As such, it is impossible to interact with the ghosts.
Even so, the player walks forward when facing the butler and turns to the left side, where the ghost appears to be walking.
