Once when Pac-Man was still young, he spent a summer at the home of the great Pac-Master for training to fight the ghosts in Pac-land. During Pac-Man's training, Pac-Master's family went to the power pellet Harvest Festival with Pac-Man. The Ghosts (possibly young too) decided to summon the legendary ghost, Golvis. He was said to be so strong that he was sent to space by the ghosts themselves. Castle Pac were celebrating the large crop of power pellets gathered, when the Harvest Festival was suddenly disturbed by a UFO from which Golvis comes. In an attempt to save the Pacs, Pac-Master chomped on a power pellet. But while the other ghosts turned blue, Golvis remained his normal colour with only the end of his tail blue. Golvis and his alive guitar sidekick (possibly named Jack) turned the pac-people into spheres (they are the same just without arms or legs), and kidnapps them all. With the help of Pac-Land's guardian fairy, Crystal, Pac-Man managed to escape before getting kidnapped.
Now with the help of Crystal, Pac-Man (who has been put on Golvis' sphere curse) must save Pac-Master's family from the evil Golvis and Ghosts, with their evil plot to turn Pac-Land into Ghost-Land.
Source: Wikipedia, "Pac 'n Roll", available under the CC-BY-SA License.