The story begins with King Dedede returning to his castle after a long battle with Kirby. His wife, Queen Cecece, abuses him for his constant failure and claims he is unfit to rule Dream Land. At that moment, their son Bebebe zips by on a Wheelie, jumps off, and nominates himself as new king. As the squabbling escalates, Dedede decides to decide this the old-fashioned way: A fight-to-the-death in the Grandmaze.
The three do their best to survive in the Grandmaze, overcoming the obstacles and fighting themselves (as well as Gimmick V) multiple times. As the game progresses, they all come to the realization that they just want their family back. As the three meet with Gmmick V, the Grandmaze software breaks free of its shell. The free software then causes a maze-effect to envelop Dream Land. It is seen that people can only take 3 steps in their own room before getting lost.
Gimmick V still perceives the Grandmaze as a simple maze, and claims that he knows of a vulnerable point. He then embarks, with the player seeing things through his eye. When he reaches the center, he destroys the Grandmaze.
After Gimmick V is found upside-down in a royal fountain, he states "This ain't over". The Dedede family make amends, and King Dedede grants Gimmick his freedom and a kngihthood for services. The game ends with the royal trio bidding the robot farewell.
(in order of appearance)
King Dedede- Self-proclaimed King of Dream Land. His wife and son are giving him trouble, so he has imprisonned himself and them in Maze. He is vulnerable to his wife's scolding and has a soft spot for his son.
Queen Cecece- Dedede's wife. It is unknown why a beautiful human married Dedede, but they do say that "Love has no boundaries". She is tired of her husband's perpetual failure, and plans to succeed him. She is the firm hand in the family, with a hold of terror over her husband and son.
Prince Bebebe- The heir to the throne and a righteously spoiled brat. He spends most of his time riding around the courtyards on any of the many mechanical minions his father's factories can dish out.
KAOS-com- The only truly evil character. KAOS-com is an alien robot, who sent the Grandmaze to Dream Land. He remotely controls it, and it appears to be an extension of his software.
Gimmick V- The deadliest robot ever known. His one weapon is a yo-yo, which he has used to survive in the Grandmaze for fifty years. If the Grandmaze doesn't get you, Gimmick V will. At least, that's his intended purpose.