Shio is a sixteen-year-old high school student whose life changes overnight when his mother remarries, suddenly giving him three older stepbrothers. The four of them begin living together as the Wada family, with Shio taking on most of the household chores and quickly becoming the heart of the home. Each brother adores him in his own distinct way: Fuji, the twenty-six-year-old eldest, is cool and reserved but deeply caring; Taka, twenty-three, is outgoing and handsome, showering Shio with open affection; and Mina, twenty, looks cute and innocent but has a calculating, slightly mischievous side.

The early chapters focus on the warm, comedic chaos of four brothers sharing a life. Shio’s pure and earnest nature softens every situation, while his brothers compete to pamper him. Beneath the surface, however, a more complicated undercurrent stirs. Fuji is the first to notice that Taka’s feelings for Shio go beyond brotherly love. Taka himself becomes increasingly aware of his own romantic attraction, and the story gradually shifts from lighthearted family comedy to a gentle exploration of feelings that blur the line between familial and romantic bonds.

As the narrative progresses, a key episode at a seaside inn forces Shio to confront old childhood loneliness, and Taka comforts him in a moment that deepens their connection. Later, Shio’s biological mother reappears, threatening to tear the newly formed family apart, but the brothers rally together. Taka eventually confesses his love openly, and Shio begins to sense his own changing emotions. Meanwhile, Fuji and Mina also harbor their own quiet attachments, creating a delicate balance of competing affections.

The story concludes after twelve chapters, emphasizing the strength of the Wada brothers’ bond. Taka’s confession is accepted in a way that preserves the family unit, and the final scenes show the four of them continuing their lively, affectionate daily life together—Shio still the sun around which his brothers orbit, their various feelings left as a warm, unresolved “something” that makes their household uniquely complicated and heartening.