Like most of her classmates, Koyuki Honda eagerly anticipates the graduation ceremony. While many of her friends have relatives to attend, Koyuki is left alone; the only family she had—her brother—passed away years earlier. During a visit to his grave, she encounters two siblings named Kiri and Victor Putin who are in pursuit of a bizarre creature. They assure her they are merely actors filming a scene, but Victor sparks Koyuki"s interest in an ancient tale about the cemetery"s clock tower: if one makes a wish beneath it at midnight on a full moon, time reverses and allows the lost to be regained.
Choosing to try the wish, Koyuki discovers a chilling reality: the story is a façade used by time‑devouring demons called "Horologues" to siphon human moments. Drawn by sorrow, Victor lures a demon toward her as bait. Kiri and Victor reveal themselves as Chronos Rulers, warriors who combat the Horologues with the "Oath of Time"—a relic that can accelerate or decelerate moments.
After vanquishing the demon and averting disaster, Koyuki walks away unburdened by regret. Yet she is not the sole human burdened with grief. The two brothers must keep hunting Horologues to protect humanity. Their relentless pursuit ensures that the fragile threads of time remain intact for future generations while the world sleeps, deeply quiet.
