Set in the final years of Japan's shogunate, all characters from the main series, Silent Mobius, appear with the same name. According to the setting, they are said to be the previous lives of the characters in the main story...

In Earth Defense Girl Iko-chan 2: Lunna's Secret, the mantle of Earth Defense Girl is passed to a new hero after the retirement of Iko Kawai. The new Iko-chan must protect Earth from a new threat, all while navigating the chaos of battling monsters and saving the day.