Experience the nostalgic story from the Pokémon Diamond Version game in a reimagined adventure, Pokémon Brilliant Diamond, now on the Nintendo Switch system! Adventures in the Pokémon Brilliant Diamond game will take place in the familiar Sinnoh region. Rich in nature and with mighty Mount Coronet at its heart, Sinnoh is a land of many myths passed down through the ages. The Underground from the Pokémon Diamond Version game has been powered up and is now called the Grand Underground.