After his younger sister suddenly starts acting differently around him, the everyday life in Brother, Am I Cute? begins to change in unexpected ways. What once seemed like normal sibling interactions slowly turns into a series of funny situations, confusing emotions, and heartfelt moments as the characters try to understand each other better. The manga focuses on their daily conversations, small misunderstandings, and the growing changes in their relationship while mixing comedy with emotional storytelling. With charming character expressions and a light atmosphere, Brother, Am I Cute? delivers a sweet slice-of-life experience centered around family bonds, youth, and the awkward feelings that appear while growing up.