"Osomatsu-san" is a comedic anime series that serves as a modern reboot of the classic 1960s manga and anime "Osomatsu-kun." The story revolves around the Matsuno sextuplets—Osomatsu, Karamatsu, Choromatsu, Ichimatsu, Jyushimatsu, and Todomatsu—who are now adults in their twenties, still living together and struggling to find purpose in life. Despite their identical appearances, each brother has a distinct personality: Osomatsu is the lazy but self-proclaimed leader; Karamatsu is narcissistic and melodramatic; Choromatsu is the most responsible and career-focused; Ichimatsu is socially awkward and pessimistic; Jyushimatsu is eccentric and hyperactive; and Todomatsu is cunning and image-conscious.

The series lacks a continuous overarching plot, instead presenting episodic, self-contained stories that often parody various genres, tropes, and cultural phenomena. The Matsuno brothers frequently engage in absurd, chaotic antics, ranging from attempting to find jobs or girlfriends to getting caught up in bizarre situations like time travel, supernatural encounters, or even breaking the fourth wall. Their interactions with recurring side characters, such as their childhood friend Totoko, the wealthy but naive Iyami, and the mysterious Chibita, add to the comedic and unpredictable nature of the series.

"Osomatsu-san" blends slapstick humor, satire, and meta-commentary, often poking fun at societal norms, pop culture, and even its own legacy as a reboot. The show’s humor is frequently over-the-top, with rapid-fire jokes, exaggerated reactions, and surreal scenarios. Despite its comedic tone, the series occasionally delves into more introspective moments, exploring themes of failure, identity, and the challenges of adulthood, though these are always framed within its absurdist style.

The anime’s structure allows for a wide range of storytelling, from parodies of other anime and TV shows to original, character-driven narratives. The Matsuno brothers’ dysfunctional yet endearing dynamic remains the core of the series, with their individual quirks and relationships driving much of the humor and emotional resonance. "Osomatsu-san" is a chaotic, irreverent comedy that thrives on its unpredictability and its ability to balance absurdity with moments of genuine character insight.