Himouto! Umaru-chan is a lighthearted comedy anime centered around Umaru Doma, a high school girl who leads a double life. In public, she is the epitome of perfection: beautiful, intelligent, and talented, earning admiration from her peers. However, once home, she transforms into a lazy, chibi-like "himouto" (a portmanteau of "himono," meaning dried fish, and "imouto," meaning little sister). In this state, she spends her time indulging in junk food, video games, and anime while leaving all household responsibilities to her hardworking older brother, Taihei. The comedic premise revolves around the contrast between her two personas and the challenges Taihei faces in managing her antics.

As the series progresses, Umaru's interactions with her friends and family flesh out the story. Her classmates Nana Ebina, a shy and kind-hearted girl, and Sylphynford Tachibana, a competitive yet friendly rival, both contribute to the comedic and heartfelt moments. Another character, Kirie Motoba, initially timid and awkward, grows closer to Umaru through her fascination with her alter ego, "Komaru." These relationships help Umaru navigate her unique lifestyle while blending her hobbies and responsibilities, creating relatable and humorous situations.

The anime blends humor with subtle moments of growth, exploring themes of sibling bonds, friendship, and self-acceptance. Taihei’s patience and care for his sister, despite her laziness, highlight the strong familial connection between them. Umaru's eventual realization of her brother’s efforts and the importance of her friendships adds depth to the otherwise comedic series. Himouto! Umaru-chan appeals to viewers with its quirky humor, charming characters, and slice-of-life storytelling.