"Is It Wrong to Try to Pick Up Girls in a Dungeon?" is set in the fictional city of Orario, a bustling hub where adventurers gather to explore the Dungeon, a vast labyrinth filled with monsters and treasures. The story centers on Bell Cranel, a young and inexperienced adventurer who dreams of becoming a hero. Bell is the sole member of the Hestia Familia, a small group led by the goddess Hestia, who deeply cares for him. Hestia, though kind-hearted, struggles to provide resources for Bell due to the familia's limited influence and size.

Bell's journey begins with his near-death encounter with a powerful monster in the Dungeon, where he is saved by Ais Wallenstein, a renowned swordswoman from the Loki Familia. Inspired by Ais's strength and beauty, Bell becomes determined to grow stronger and earn her recognition. His rapid growth, fueled by a unique skill called "Realis Phrase," which accelerates his development based on his feelings for Ais, draws attention from other adventurers and deities.

As Bell progresses, he forms bonds with various characters, including Eina Tulle, his advisor at the Guild, and Welf Crozzo, a blacksmith who joins the Hestia Familia. He also encounters Lili, a supporter from the Soma Familia, who initially deceives him but later becomes a loyal ally. Bell's adventures often involve overcoming challenges within the Dungeon, such as battling powerful monsters, navigating its treacherous floors, and uncovering its mysteries.

The narrative also explores the dynamics between familias, the divine factions led by gods and goddesses who grant their followers powers. The Hestia Familia's rise attracts both allies and rivals, including the antagonistic Apollo Familia, which seeks to claim Bell for their own. The series delves into themes of perseverance, camaraderie, and the pursuit of dreams, as Bell strives to prove himself in a world where strength and status are paramount.

Throughout the series, Bell's growth as an adventurer is paralleled by his deepening relationships with those around him, particularly Hestia, who harbors romantic feelings for him. The story balances action, humor, and emotional moments, creating a compelling tale of ambition and self-discovery set against the backdrop of a richly detailed fantasy world.