Pokémon Mystery Dungeon: Explorers of Time and Pokémon Mystery Dungeon: Explorers of Darkness are a matched pair of Pokémon games developed by Chunsoft and published by The Pokémon Company and Nintendo for the Nintendo DS. The two games were released in Japan in September 2007 and in North America and Europe in 2008. A third version Pokémon Mystery Dungeon: Explorers of Sky was released for the same hardware in 2009. As a sequel to Pokémon Mystery Dungeon: Blue Rescue Team and Red Rescue Team new features include the addition of Generation IV Pokémon improved Wi-Fi functionality and more touch-screen options. The games feature 491 of the 493 Pokémon as Shaymin and Arceus were not officially revealed at the time of the game's launch.