"Abunai Sisters" centers on the comedic and often absurd adventures of two sisters, Koko and Mika, who work as private detectives in Tokyo. The series blends slapstick humor, parody, and over-the-top scenarios, often satirizing popular anime and manga tropes. Koko, the older sister, is portrayed as a confident and flamboyant character, while Mika, the younger sister, is more reserved and pragmatic. Their contrasting personalities frequently lead to humorous misunderstandings and chaotic situations.

The narrative unfolds through episodic cases, with the sisters tackling a variety of bizarre and exaggerated mysteries. These cases often involve eccentric clients, absurd villains, and surreal plot twists. The series frequently breaks the fourth wall, with characters acknowledging their roles in a fictional story and directly addressing the audience. This meta-humor is a recurring element, adding to the show's self-aware and comedic tone.

Supporting characters include a range of quirky individuals, such as their bumbling assistant, a rival detective, and various one-off antagonists. The interactions between these characters further amplify the series' comedic style, often relying on exaggerated reactions and absurd dialogue. The plotlines are intentionally nonsensical, prioritizing humor and parody over coherent storytelling.

Themes of sisterhood and teamwork are present, though they are secondary to the comedic elements. The series does not delve deeply into character development or emotional arcs, instead focusing on delivering rapid-fire jokes and visual gags. The humor often references pop culture, anime conventions, and societal norms, making it accessible to audiences familiar with these contexts.

Overall, "Abunai Sisters" is a lighthearted, satirical series that thrives on its absurdity and comedic timing. Its episodic structure and reliance on parody make it a distinctive entry in the comedy genre, appealing to viewers seeking a break from more serious or plot-driven narratives.