The series revolves around the life of the protagonist, who is a high school student. His daily life becomes more complicated with the arrival of his little sister, who is exceptionally cute and energetic. The sister, named Miri, is a precocious and lively elementary school student who often gets into mischief, causing her brother to roll his eyes in exasperation. Despite their sibling rivalry, the two share a deep bond, and their interactions are filled with humor, warmth, and heart.
: Cute character designs and marketing strategies leveraging the charm of siblings or young characters have proven successful in the merchandise market, selling everything from figurines to plush toys. uchi no otouto maji de dekain.