Warning: Major spoilers for Serika’s route contained below.
The theme of the route is still family, but unlike in the previous route, it addresses not so much the transition of family to lovers, but lovers to family.
While Kasumi tried to be considered a platonic older sister to Shinichi, unwilling to acknowledge her romantic desires, Serika accepts their familial roles with surprising grace, but makes no such attempt to prevent their relationship from developing into something deeper, and things quickly escalate into physical intimacy. Whereas Kasumi suffered from guilt for loving her step-brother, and thus ruining the familiar family dynamic, Serika has been enamored with Shinichi since they were children, and never felt that platonic bond as strongly as her sister.
The Serika in this route is not the same girl burdened with the anguish of tearing apart her sister and her lover, and as such, she is much more confident and direct in pursuing Shinichi. Beneath her teasing remarks and temperamental outbursts, we are introduced to a much softer, affectionate side of her, but such honesty also comes with its flaws. Serika, in spite of her harsh exterior, is very emotionally vulnerable, desperate for the love of others.
While her relationship with Shinichi flourishes, she is at her brightest, but their happiness is stifled by the need to keep it a secret from both their families and friends. They are still step-siblings, after all, and the taboo of incest weighs heavily upon the new brother and sister, no matter how much they attempt to ignore the inevitable consequences of their actions. However, the threat of discovery becomes too much to bear when they begin to draw suspicion, and Shinichi puts a swift end to their romantic overtures. Instead, he insists on returning to strictly platonic behavior with Serika, but the resulting development is even worse than their previous friendship.
While Shinichi prevents her efforts to rekindle their passion, Serika is utterly heartbroken by the isolation between them. She denies any issues in their coupling, asking for kisses and even taking Shinichi out on one-sided dates, only to be denied with each increasingly desperate appeal. Even when there are no witnesses, he refuses her advances still, forcing her to a breaking point.
It is only through the advice of friends does Shinichi realize how much Serika has endured, and that suppressing his emotions is only causing both of them to suffer. Yet his revelation comes possibly too late, as Serika plans to run away from home, feeling unwanted by Shinichi and unneeded by her family. However, after a confrontation between the two, they realize the most important thing is not the disapproval of others or the roles placed upon them, but their own happiness as a couple.
Unfortunately, I do have to note that while Kasumi’s route involved both sisters, each with crucial importance, the lack of a love triangle in this route means Kasumi’s presence was severely diminished. Still, this is a minor complaint. The romance was as sweet as promised, the dramatic tension was heartbreaking, and Serika blossomed in a way she was never given the chance to before. This transformation, finally revealing the true depths of her character which were only hinted at in other routes, is immensely rewarding in itself. No matter how simple or complex, it is the heroine who carries the heart of the story, and Serika is a wonderful one.