プラネットガーディアン

When a fateful shooting star streaks across the night sky, fourth-grader Koyuki Kisaragi encounters an alien who delivers a dire warning: Earth is in grave danger from an invasion by the sinister "Algol." Entrusted with the role of a magical guardian, Koyuki must balance her carefree childhood with the weight of protecting the planet. Joined by her fellow guardians, including the overly enthusiastic Ririka and the enigmatic Shizuku, Koyuki faces off against cosmic threats while navigating the chaos of school life and family. (Unreviewed summary by Grok 2)