Su-Ae Sim struggles in a relationship with her disinterested boyfriend, Min-U Kang, longing for the confidence of her stepsister, Ra-Im. However, her world shifts when she stumbles upon Jellypop, a sentient flip phone with insights into her love life. As Su-Ae's bond with Min-U weakens and she crosses paths with his friend, Eun-Hyeok, suspicions of a deeper connection between Min-U and Ra-Im emerge. Navigating the complexities of high school romance, Su-Ae faces a rollercoaster of emotions and uncertainties, hoping for a miracle to guide her through the twists and turns ahead.