Miki Koishikawa's serene high school life takes a tumultuous turn when her parents announce their divorce post a 'fun' Hawaiian vacation. The shock amplifies when they reveal plans to remarry another couple they met on the trip, intertwining their lives. While grappling with this upheaval, Miki finds herself drawn to the charming son of the new couple, Matsuura Yuu. What blossoms as a friendship soon blooms into a forbidden romance, fraught with obstacles from jealous admirers intent on driving them apart.