In the future, Earth faces an energy crisis due to a scarcity of dark matter, the primary fuel source for space travel. Professor Farnsworth discovers a potential solution in a dangerous and guarded dark matter mine. Meanwhile, Bender, the robot with a highly active imagination, starts experiencing delusions of grandeur after becoming addicted to playing a Dungeons & Dragons-style fantasy game. In an attempt to cure Bender's mania, the crew of Planet Express embark on a quest that leads them into unexpected territory.

As they delve deeper, the narrative takes an imaginative turn, blurring the lines between reality and Bender's fantasy world. Here, characters assume medieval roles, facing mythical perils and strange creatures. The story intertwines their quest to solve the dark matter puzzle with their struggles in the fantastical land, revealing hidden truths about their mission and themselves. Balancing humor and adventure, the film explores themes of identity, imagination, and the pursuit of energy solutions in a uniquely twisted way.