The Old Chateau is one of the more mysterious areas in the Sinnoh region. You’ll pass by it on your way to fight Pokémon Brilliant Diamond and Shining Pearl’s second gym leader, Gardenia, but you won’t be able to access it at first. Here’s how to get inside the Old Chateau, and a rundown of what you can expect to find inside this haunted mansion.
Firstly, you’ll need to acquire the TM 93 Cut, which allows you to chop down small trees in your path. To get this ability, you need to perform two tasks: Defeat Gardenia at her gym in Eterna City, and then approach the building above the PokéCenter in Eterna City. A mysterious stranger who you may or may not recognize will appear and give you the TM, allowing you to explore new areas.
You’ll find the Old Chateau in Eterna Forest, right outside Eterna City. If inside the city, exit via Route 205 and follow the path into the forest. Once in the forest, you should see two small trees blocking a hole in a fence. Use cut to clear these and advance through the newly-formed entryway. You’ll then arrive at the Old Chateau.
The Old Chateau is haunted, and as such, it’s filled with Ghost-type Pokémon; if you’re looking for a Gastly, this is where you’ll want to go. Additionally, you can find some pretty unique items here, such as the Old Gateau — a one-time use item that can heal any status ailments a Pokémon is suffering from. The Old Chateau is also home to Rotom, but you won’t be able to encounter it until after you’ve beaten the game and unlocked the National Pokédex.
