Pokemon Diamond and Pearl Adventure!, Vol. 8 by Shigekatsu Ihara
If Hareta and his new rival Koya can't agree on how to rescue Cyrus and a group of mind-controlled Pokemon, they might never get saved! Then Koya is attacked by a long-lost Pokemon friend... And when Hareta finally gets his chance to battle the legendary Pokemon Giratina, two unexpected allies arrive to fight by his side!.