The Pokémon Mystery Dungeon series, published by Nintendo and developed by Chunsoft, is a series based on the Pokémon RPG franchise. The first two games in the series, Pokémon Mystery Dungeon: Blue Rescue Team/Red Rescue Team were released on September 18, 2006. The second installments of the series, Pokémon Mystery Dungeon: Explorers of Time/Darkness, were released on April 20, 2008. Pokémon Mystery Dungeon Explorers of Sky was released in October, 2009.