Ane ni Naritai Ane VS Yuri ni Naritai Imouto

When Shio returns home one ordinary day, she is met with a sudden and life-altering announcement: her mother has remarried. To make matters more complicated, her mother immediately departs on a business trip alongside her new husband, leaving Shio alone in the house with her newly acquired stepsister, Kafka. The two girls are practically the same age, separated by a mere single day, yet that tiny gap is enough to ignite an unexpected domestic rivalry. Anxious about her standing in this restructured household, Shio becomes deeply concerned that Kafka will attempt to usurp her role as the elder sister. She is determined to protect her position and maintain the authority that comes with being born just twenty-four hours earlier. However, Kafka harbors a far different agenda entirely. Rather than competing for sibling hierarchy, she is driven by a long-held romantic affection. Unbeknownst to Shio, Kafka has secretly carried feelings for her for quite some time, viewing her new stepsister as her very first love. Now living under the same roof without their parents around, Kafka seizes the opportunity to pursue her true intentions. As Shio fights to assert her seniority, Kafka sets out on a devoted mission to make her fall in love, transforming their shared home into a battleground between sisterly pride and romantic desire.