Jak & Daxter: The Lost Levels

On a world with the ruins of the mysterious Precursors, including their robots, two disobedient boys from the southern tip of the continent go to Misty Island. There they witness an old man and beautiful woman leading the Lurkers, trying to gain power over eco. When Jak and Daxter try to escape, one of the lurkers chases them, and Daxter falls into dark eco and emerges as an ottsel. The only way for them to change him back is to go to a wise old sage who lives far to the north, but they need to bring Keira eight power cells to get to Rock Village.