I won't stop. Until the day I become a knight of justice. The interstellar nation of the Algrand Empire - its frontier territory of Banfield. A young girl named Emma admires the lord who saved her when she was young, and after working hard, she finally takes her first steps as a "knight". "I will... be a knight of justice!" However, after making a huge mistake in her first battle, she is deemed incompetent and ordered to be demoted to the frontier planet Aerias. Feeling powerless, Emma is about to give up on being a knight when the mobile knight who once saved her from a difficult situation appears before her――!?