"Is It Wrong to Try to Pick Up Girls in a Dungeon? IV" continues the adventures of Bell Cranel, a young adventurer striving to grow stronger while navigating the dangers of the labyrinthine Dungeon. This season delves deeper into the mysteries of the Dungeon and the challenges faced by Bell and his allies. The narrative centers on the "Xenos Arc," which introduces a group of sentient monsters known as the Xenos, who possess human-like intelligence and emotions. These creatures challenge the traditional perception of monsters as mindless enemies, creating moral and ethical dilemmas for Bell and other adventurers.

As Bell encounters the Xenos, particularly a dragon-like creature named Wiene, he begins to question the established norms of adventurers slaying monsters. Wiene forms a bond with Bell, who vows to protect her from those who seek to destroy the Xenos. This decision puts Bell at odds with other adventurers, including members of his own familia, as well as powerful factions like the Ikelos Familia, who view the Xenos as threats to be eradicated. The season explores themes of coexistence, prejudice, and the blurred lines between friend and foe.

The plot intensifies as Bell and his allies, including Ais Wallenstein, Ryuu Lion, and members of the Hestia Familia, navigate the treacherous Dungeon to uncover the truth about the Xenos. The story also highlights the political and social tensions within Orario, as the existence of the Xenos threatens to disrupt the balance of power among the city's familias. The season builds toward a climactic confrontation in the Dungeon, where Bell must defend the Xenos while grappling with his own ideals and the harsh realities of the adventurer world.

Character development remains a key focus, with Bell's growth as a leader and his unwavering determination to protect those he cares about taking center stage. The relationships between Bell and other characters, such as his mentor Hestia and his rival Ais, are further explored, adding depth to the narrative. The season balances action-packed sequences with emotional moments, creating a compelling story that advances the overarching plot of the series while introducing new layers of complexity to its world and characters.