The warrior Rance, his faithful slave Sill Plain and his not-quite-as-faithful pet Athena 2.0 are out adventuring in an attempt to regain their money, all of which Rance had spent earlier playing around. Their travels lead them to a mysterious cave, in which all three become lost. Rance successfully reunites with Sill and, agitated over getting stuck and indifferent to Athena's well being, attempts to exit the cave, only to find himself becoming even more lost in the process.

The duo briefly encounter Rance's longtime "rival" Bird Lithfie, who has begun dating Copandon Dott, a girl obsessed with finding a man who possesses great luck. On a journey to find the fabled "land of happiness" together, the couple also became trapped in the cave. Rance attempts to steal Copandon away from Bird, but is refused due to Copandon's belief that Bird is the "great luck guy" that she seeks.

Following this, Rance and Sill stumble into a mysterious town inhabited by various strange creatures known as Youkai. Within this town, the pair learn that they have inadvertently entered into Genbu Castle, a pocket dimension in which time stand still and from which escape is seemingly impossible. Horrified at the idea of never being able to partake in the women of the outside world again, Rance quickly begins searching for a way out. Along the way, he is targeted by Rizna Lanfbitt, an enigmatic woman who seeks to manipulate him into assisting her in exiting Genbu Castle on her own. Instantly taken in by her beauty, Rance agrees to help Rizna in the hopes of eventually being able to have sex with her.

Meanwhile, Bird and Copandon discover a treasure chest containing the rare Gal Monster Lil Avenger, a master assassin who will exterminate whoever the person that discovers her tells her to. After Bird accidentally(?) tells her to target Rance, the Gal Monster begins her relentless pursuit to take his life.

Even when he is trapped in a world beyond time and fighting for his life at every second, Rance still chooses to prioritize finding every beautiful girl that he can and having sex with them over looking for a means of escape. And so, a new chapter of the brutal legend begins...