Due to her father's remarriage, Ema's family dynamics suddenly shift with the arrival of her new stepsister. Her father leaves on a honeymoon, leaving Ema alone with her stepsister, with whom she hasn't yet grown comfortable. The stepsister acts strangely—initiating sudden kisses and closing the distance too quickly, making Ema feel uneasy. Amid this tension, Ema gets dumped by her boyfriend and sinks into despair. In her vulnerable state, she opens up to her stepsister, leading them into a forbidden relationship. As her feelings for her stepsister deepen, Ema finally gives in completely.