"Impregnable Walnut Swamp" or more naturally: "The Unassailable Walnut Swamp"

Sato Shu enters high school. Hoping for the sexual developments he couldn't experience in middle school, he enters high school. On his first day of school, he confesses to Kurumi Kuromasawa, a half-Japanese girl with silver hair and beautiful features, and they start dating. However, Shu didn't know. That his girlfriend was known in middle school as the impregnable Kuromasawa, who had rejected countless boys. And that she had decided she would absolutely never do anything sexual before marriage. A youth romantic comedy between Sato Shu, who wants to do it, and Kuromasawa, who will absolutely not let him. Will Shu ever be able to get into bed with his girlfriend?