"The Prince of Tennis II: U-17 World Cup Semifinal" continues the narrative of the U-17 World Cup arc, focusing on the intense semifinal matches between Japan and Germany. The series delves into the high-stakes competition as the Japanese team, led by Ryoma Echizen and other talented players, faces off against the formidable German team, which includes world-class players like Jürgen Boris Volk and Tezuka Kunimitsu, a former captain of the Japanese team now representing Germany. The semifinal is structured as a series of singles and doubles matches, each showcasing the unique skills and strategies of the players.

The Japanese team, determined to prove their strength on the global stage, must overcome the overwhelming power and precision of the German team. Key matches include Ryoma Echizen's confrontation with Tezuka, highlighting their complex mentor-student relationship and the evolution of Ryoma's abilities. Other standout moments involve the doubles matches, where players like Kintarō Tooyama and Atobe Keigo demonstrate their growth and adaptability under pressure. The series emphasizes the psychological and physical challenges faced by the players, as well as the camaraderie and rivalry that drive them to excel.

The narrative also explores the broader context of the U-17 World Cup, with glimpses into the strategies and dynamics of other competing nations. The semifinal serves as a critical turning point, testing the limits of the Japanese team's resolve and skill. The series maintains a focus on the technical aspects of tennis, with detailed depictions of advanced techniques and match strategies, while also highlighting the personal growth and relationships of the characters. The outcome of the semifinal sets the stage for the climactic final matches, underscoring the high stakes and global significance of the tournament.