After having descended upon this world, the gods have created guilds where adventurers can test their mettle. These guilds, known as "familia," grant adventurers the chance to explore, gather, hunt, or simply enjoy themselves. Dungeon ni Deai wo Motomeru no wa Machigatteiru Darou ka Gaiden: Sword Oratoria begins in Orario, the lively city of adventures. The Sword Princess, Ais Wallenstein, and the novice mage, Lefiya Viridis, are members of the Loki Familia, who are experts at monster hunting. With the rest of their group, they journey to the tower of Babel in hopes of exploring the dungeon underneath. Home to powerful monsters, the dungeon will fulfill Ais's desire to master her sword skills, while bringing Lefiya closer to her dream of succeeding Riveria Ljos Alf, vice-captain of the Loki Familia, as the most powerful mage in the land.

In response to the worsening crime rate, Japan creates Tokyo Butei High, an elite academy where "Butei" or armed detectives hone their deadly skills in hopes of becoming mercenary-like agents of justice. One particular Butei is Kinji Tooyama, an anti-social and curt sophomore dropout who was once a student of the combat-centric Assault Division. Kinji now lives a life of leisure studying logistics in order to cover up his powerful but embarrassing special ability. However, his peaceful days soon come to an end when he becomes the target of the infamous "Butei Killer," and runs into an emotional hurricane and outspoken prodigy of the highest rank, Aria Holmes Kanzaki, who saves Kinji's life and demands that he become her partner after seeing what he is truly capable of.

Chisato Mizusawa is a calm and collected assistant office manager who apparently dislikes drinking alcohol. But she actually likes it and has a secret side to her that emerges only when drunk: her cute persona, which she only reveals to her husband, the bartender Sora. Each day when Chisato comes home, Sora takes care of his beloved wife, providing her with a good meal and a fresh drink. These drinks include Plum Splet, Irish Coffee, Orange Breeze, and many more tasty concoctions that she eagerly gulps down. But as much as she likes alcohol, she loves her kindhearted husband more. Together, they share a life that is filled with happiness—and the more-than-occasional cocktail. [Written by MAL Rewrite]