Ao no Hako, also known as Blue Box, is a sports-themed manga series that follows the story of Taiki Inomata, a high school student who dreams of becoming a professional badminton player. The series blends romance and sports, focusing on Taiki's interactions with his crush, Chinatsu Kano, who is also an athlete. The narrative delves into themes of perseverance, young love, and the challenges of balancing sports and personal life.