There are three games in the Explorers set: Explorers of Time, Explorers of Darkness, and Explorers of Sky. Time and Darkness were released for the DS in 2007 in Japan and 2008 elsewhere. These games contain the first 491 Pokémon in the National Pokédex (Bulbasaur through Darkrai). Explorers of Sky was released in 2009 with some quality-of-life changes and additional content, including the ability to recruit Shaymin and a cameo from Arceus.