A special program based on a Nintendo DS game "Pokemon Mystery Dungeon: Explorers of The Sky" was announced to be aired on April 12th preceding the release of the game on April 18th. The game is a new version of "Explorers of Time and Darkness
" with additional episodes.
A boy is teleported into the Pokemon world and turned into Piplup. He sets out for an adventure with Chimchar and Grovyle to save the world by "Gear of Time" hidden in "Phantom Land".
Source: Pokemon Official Website