Pacster (often known as Pac-Man) is a young Pac-Man with a belief for ghosts and a big appetitie. He has been oprhaned since he was young and lives in his dormitory. He has two best friends: Spiral and Cylindria, who support him all the way. One day, Pacster got lost in the school's maze and accidentally finds himself in an unknown ruin. His stumble inadvertently opens a gate to the netherworld, where ghosts now haunt and terrorize Pac-World. Along with this, an evil mastermind known as Betrayus has appeared and vowed to dominate Pac-World after being banished for years. The series follow Pacster and his friends as they embark on an adventure and heroism as they bust ghosts and stop Betrayus from conquering Pac-World.