My Stepmom's Daughter Is My Ex

High school was supposed to be the ultimate fresh start, a chance to leave behind the wreckage of a disastrous middle school romance. For one young man, it promised to be a peaceful sanctuary where he would never have to see his ex-girlfriend again. That dream shatters completely when he discovers that his former partner has not only enrolled in his exact high school but has also become his new stepsibling after their parents' marriage. What should have been an escape quickly transforms into an inescapable reality, as she is now everywhere he looks—in his home, his classroom, and his daily life. To make matters worse, she audaciously insists on being treated as the older sibling, a claim he vehemently refuses to accept given his own status in their newly blended family. Despite the constant proximity, both are determined to keep their romantic history firmly in the past. Having already witnessed each other's worst traits during their failed relationship, they know without a doubt that they were never truly meant for one another. To preserve their parents' happiness, they agree to maintain the facade of friendly, cooperative siblings. However, beneath this carefully constructed act, they remain stubborn rivals. No matter how hard they try to play the part, returning to anything resembling their old dynamic is entirely out of the question.