Megumi Iijima hails from the year 2112, a future ravaged by monstrous replinoids. Dispatched back through time to the late 20th century, she infiltrates a Japanese school, masquerading as an ordinary student. Her critical mission is to locate the one individual capable of wielding a unique futuristic sword, the key weapon needed to fight the replinoids and halt their brutal subjugation of women.

Operating undercover, she partners with a male student, Narita. They investigate the mysterious disappearances of female classmates, leveraging Iijima's future knowledge and deductive skills to uncover replinoid involvement. Publicly, she voices disapproval of Narita's habit of spying on girls, though this criticism masks her concealed feelings for him.

Her existence as a time traveler forged her focused, determined nature. The narrative concludes unresolved, leaving her mission's success uncertain and the fate of figures like Saotome hanging in the balance.