The older sister is Ichika, now a middle school student, while the younger sister is Kotone, still in elementary school. Both girls are always full of energy and have lively personalities. Every summer vacation, they make it a habit to come play at my pool, arriving each year at my countryside home wearing their school swimsuits. Since I only get to see them once a year, I've looked forward to watching them gradually grow from children into young girls. Still innocent and carefree, they play around without a hint of self-consciousness, completely unfazed even as their chests begin to develop. Though I never used to think much of it, lately there's more to see, and I've started struggling to know where to look. Noticing my discomfort, Ichika leans in and whispers, "Onii-chan, your penis... it's getting big." Her words expose my true feelings completely.