A few months after his first encounter with the lost ghost Mayoi Hachikuji, Koyomi Araragi finds himself unable to locate the young lady to return her backpack. Giving up, he returns home only to realize that he has neglected to complete any of his summer homework on the final day of vacation. In desperation, he turns to the former vampire Shinobu Oshino, who resides in his shadow, asking for her help to travel back in time by a single day. Shinobu agrees, but the plan goes spectacularly wrong, and the pair overshoot their target, landing eleven years in the past on May 13th, the day before the Mother’s Day when Mayoi Hachikuji was killed in a car accident.

Recognizing the date, Koyomi sees a chance to alter history and save Mayoi from her fate, ignoring Shinobu’s stern warnings about the unpredictable consequences of changing the past. After successfully intervening and ensuring the young girl reaches her mother’s house, Koyomi and Shinobu attempt to return to their own time. However, they arrive in a present-day world that has been utterly devastated. The town is desolate and infested with hordes of zombies, transformed humans who roam the ruins at night.

The pair soon discover the catastrophic result of their actions. Because Mayoi never died, she never became the wandering ghost that Koyomi befriended. Without that friendship, Koyomi never noticed Shinobu run away from the cram school, failed to find her, and was subsequently killed by Black Hanekawa. The loss of her only companion drove the Shinobu of this alternate timeline, now fully restored as the legendary vampire Kiss-Shot Acerola-Orion Heart-Under-Blade, to lose all hope and unleash her power, vowing to destroy the world by turning all of humanity into her servants, or jiangshi. The primary conflict shifts from finishing homework to survival and atonement, as Koyomi and his Shinobu must find a way to confront the alternate, god-like Kiss-Shot and repair the fabric of time. Along the way, they encounter a hardened, 21-year-old version of Mayoi who has learned to fight for survival and delivers a crucial message from the alternate timeline’s Meme Oshino.

The main characters are Koyomi Araragi, a well-meaning but impulsive high school senior who still retains some vampiric regenerative abilities; Shinobu Oshino, an ancient, powerful vampire who has regressed to the form of a young girl and shares a deep, silent bond with Koyomi; and Mayoi Hachikuji, the ghost of a young girl who was lost on her way to her mother’s house, whose fate is the catalyst for the story’s tragedy. Yotsugi Ononoki, a strange, expressionless doll-like apparition, also appears at the beginning to foreshadow the dangers of meddling with existence.

The narrative is structured around the Mayoi Jiangshi arc, a dark exploration of time travel and its repercussions. The story moves from the familiar setting of the town and the Nadeko Snake Shrine used for time travel, to a desolate, post-apocalyptic version of the same town overrun by the undead. The arc serves as a crucial turning point, forcing Koyomi to confront the weight of his heroic impulses and fundamentally exploring the depth of his relationship with Shinobu, as the entire world hangs in the balance of their mistakes. The title Kabukimonogatari refers to a "slanted" or "tilted" attitude toward the world, a posture of a dandy, which perfectly describes the protagonists’ unconventional, bohemian approach to dealing with supernatural aberrations.