Diamond & Pearl Old Chateau
Deep at the back of Eterna Forest, the Old Chateau rots in silence behind dusty portraits. After dark, the ghost Rotom slips into a flickering television in a back room.
Old Chateau is in Sinnoh, with Eterna Forest to the south. In the story it comes after Eterna City and before Route 206.
OLD CHATEAU MAP
Off Eterna Forest, the abandoned manor spreads across two floors of dim rooms and corridors, none of it gated by an HM.
Pokemon Encounters
Most of the manor is Gastly, but a wild Gengar appears at 4 percent, a rare shot at one without trading. Rotom hides in the back-room television, ready to possess once you flip the lights at night.
Rotom
ITEMS
The haunted manor hides TM90 Substitute and a Dread Plate for Dark teams. Its oddest find is the Old Gateau, a cake that cures any status once, sealed in a back room.
TM90 Substitute
Uses HP to creates a decoy that takes hits.
TM90 Substitute
Uses HP to creates a decoy that takes hits.
Dread Plate
An item to be held by a Pokemon. It is a stone tablet that boosts the power of Dark-type moves.
Old Gateau
Old Chateau's hidden specialty. It heals all the status problems of a single Pokemon.
Antidote
A spray-type medicine. It lifts the effect of poison from one Pokemon.
Old Chateau Guide
Rotom lives in a TV in an upstairs bedroom of the Old Chateau, north of Eterna Forest behind trees that need Cut. It only stirs after dark, and only once you have the National Pokedex, so there is no daytime or pre-Dex catch. It is a plain Level 15 in Diamond and Pearl, and only gains its five appliance forms in Platinum, staying a single Electric and Ghost type here.
Only after the National Pokedex, and only with a Gen 3 game in the DS GBA slot. By default the chateau spawns Gastly, but with that cartridge inserted Haunter and Gengar join the pool once you have the National Dex, with Gengar showing up at a low rate in the painting room. Without the National Pokedex you get Gastly alone.