From Bulbapedia, the community-driven Pokémon encyclopedia.
The title card of the manga
Pokémon Mystery Dungeon: Explorers of Time and Darkness is a manga that was added into the Explorer's Guide that came with pre-ordered copies of its corresponding games, written and illustrated by Ken Sugimori. It features an unnamed boy who was turned into a Chimchar that teams up with a Turtwig. Together they form the Team Poképals and explore the world beyond Treasure Town under the guidance of the Wigglytuff Guild. It was also available to Pokémon Daisuki Club members.