Nam Haeng-sun, a former national handball athlete, runs a bustling side-dish shop while selflessly raising her fierce niece, Hae-yi, whom she loves as her own daughter. Haeng-sun is fiercely devoted, cheerful, and resilient, navigating the daily grind with a bright smile despite her personal sacrifices. Her predictable world collides with Choi Chi-yeol, a brilliant, hyper-anxious, and celebrity mathematics instructor at a prestigious private academy. Chi-yeol suffers from severe eating disorders and insomnia due to decades of relentless
academic pressure and unresolved guilt. Despite his immense wealth and fame, he finds himself physically unable to digest any food except for the homemade side dishes lovingly prepared by Haeng-sun.Seeking a culinary cure for his chronic ailment, Chi-yeol strikes a secretive deal with Haeng-sun: he will personally tutor Hae-yi in elite mathematics in exchange for a steady supply of her nourishing meals. As Chi-yeol spends time in Haeng-sun’s warm domestic orbit, his cynical exterior melts away, and he gradually falls in love with her vibrant energy and unwavering authenticity. Haeng-sun similarly finds herself drawn to the eccentric, vulnerable genius, and their professional arrangement blossoms into a tender, heartwarming romance.However, their budding relationship faces intense opposition. The cutthroat world of elite private education is unforgiving, and Haeng-sun becomes the target of vicious snobbery from other mothers and academy directors who despise her working-class background and unorthodox methods. The scandal threatens Chi-yeol’s prestigious career, forcing them to weather intense public scrutiny, rumors, and societal pressures together.Simultaneously, a much darker threat emerges. A mysterious string of murders plagues the neighborhood, targeting individuals who have crossed paths with Chi-yeol or Hae-yi. It is eventually revealed that Chi-yeol’s seemingly mild-mannered and loyal assistant, Ji Dong-hee, is a deeply disturbed psychopath harboring an obsessive, lethal fixation on protecting Chi-yeol from anyone he perceives as a threat or a distraction. Dong-hee begins tormenting Hae-yi and eventually kidnaps Haeng-sun, driving the narrative to a tense, high-stakes climax.Chi-yeol and the police
race against time to rescue Haeng-sun. Dong-hee’s tragic past and psychological unraveling come to light before he falls to his death, finally lifting the dark cloud of terror hanging over the protagonists. With the danger neutralized, Haeng-sun and Chi-yeol emerge stronger than ever. The series concludes on a triumphant, joyful note as Hae-yi successfully passes her exams, and Haeng-sun and Chi-yeol embrace their happily ever after, proving that genuine love and resilience can conquer both the ruthless pressures of academic society and the darkest shadows of the human heart.