After their mother remarries, Marina and Airi find themselves adjusting to life with a new stepfather in the household. He quickly shows an intense interest in bonding with his stepdaughters, offering constant attention and affection that goes beyond ordinary family ties. As the sisters navigate their changing home environment, his eagerness to act as a devoted father figure creates a mix of comfort and tension. The new family dynamic promises deeper connections, yet hints at complications that test their relationships.