The Pokémon Mystery Dungeon series debuted in Japan in 2005.
Its first releases were Pokémon Mystery Dungeon: Red Rescue Team for Game Boy Advance and Blue Rescue Team for Nintendo DS. They launched in Japan on November 17, 2005, before receiving worldwide releases in 2006.
Unlike the main Pokémon role-playing games, Mystery Dungeon puts the player in the role of a Pokémon, often after a story explains that a human has been transformed. The games use randomly generated dungeons, turn-based movement, recruited teammates, and rescue missions.
Chunsoft developed the first titles, drawing on its established Mystery Dungeon roguelike format. The company later became part of Spike Chunsoft. The series expanded into several generations and platforms, but Red Rescue Team and Blue Rescue Team remain its starting point.