"Strange+" is a comedic manga series centered around the daily misadventures of Kouhei Nagano, a young man who works at a detective agency run by his childhood friend, Takumi Aizawa. The agency, located in a small, nondescript building, is far from conventional, often taking on bizarre and absurd cases that defy logic. Kouhei, who initially sought a normal job, finds himself entangled in increasingly surreal situations, often involving strange clients and peculiar phenomena.

The narrative thrives on its eccentric cast of characters. Takumi, the agency's leader, is a laid-back and enigmatic figure with a penchant for getting involved in oddball cases. His younger sister, Ayumi Aizawa, is a sharp-tongued and intelligent girl who frequently assists with investigations, often outshining her brother in wit and resourcefulness. The group is joined by Chihiro, a mysterious and androgynous individual with a calm demeanor and a knack for handling the more dangerous aspects of their cases. Rounding out the core team is Kujo, a talking cat with a sarcastic personality and a tendency to offer dry commentary on the chaos around him.

The plot is episodic, with each chapter or arc presenting a new case or scenario. These range from dealing with supernatural occurrences to solving mundane problems in hilariously over-the-top ways. The series balances slapstick humor with moments of absurdity, often breaking the fourth wall or subverting typical detective tropes. Despite the comedic tone, there are occasional hints of deeper backstories for the characters, particularly Takumi and Chihiro, though these are rarely explored in depth.

The humor in "Strange+" is rooted in its fast-paced, unpredictable nature, with a focus on visual gags, wordplay, and situational comedy. The interactions between the characters drive much of the narrative, with their contrasting personalities creating a dynamic and often chaotic atmosphere. The series does not aim for a cohesive overarching plot but instead embraces its episodic structure, allowing for a wide variety of comedic scenarios and character-driven moments.