Before the events of Bakemonogatari, Koyomi and Tsubasa delve into the mystery surrounding a stone that was enshrined into one of the school's gardens.

After Hitagi's condition is treated, she and Koyomi investigate the true reason why some flowers were left behind on a street and the school's rooftop.

After Oshino leaves the city, Mayoi informs Koyomi about a sandbox whose shape resembles a devil and he decides to find out why.

After Koyomi helps Kanbaru tidy her room, he has a bath in her house, and learns a curious story about the water of the tub.

Nadeko comes over to Koyomi's house, and is pleasantly surprised that Koyomi's parents and siblings are all absent. The two then engage in a discussion about Kaiki's curse and his means of spreading the rumor amongst the middle schoolers in town.

Karen asked Koyomi for advice regarding a mysterious grown tree that suddenly appeared on her dojo's backyard.

Tsukihi consults Koyomi regarding her Tea Club members on why her fellow members still believe in the ghostly "eight member" despite Tsukihi proving the rumor was fake.

Ougi accompanies Koyomi to the North Shirahebi Shrine, where she tells him that the shrine was originally located not on this mountain top but somewhere else.

During December, after the events of Otorimonogatari, Koyomi is sitting in his room studying for entrance exams when Shinobu suddenly appears. Koyomi, who had received donuts from Hitagi earlier in the day, decides to treat Shinobu to some of them. While inspecting the donuts, Shinobu notices that they are not "Mr. Donut" brand and states that Koyomi's girlfriend likely poisoned them. After a short argument, Shinobu eats the first donut, stating that it was delicious and insists that she thank Hitagi directly. Koyomi suggests not to, as it would be awkward for Shinobu to introduce herself on such an odd note. Soon after, Koyomi attempts to grab a donut from the four remaining, but Shinobu recoils and states the other ones might be poisoned as well. Koyomi asserts that she's exploiting the situation in order to eat the rest of the donuts, and they eventually come to a compromise, Shinobu will hide each donut around his room, and every one Koyomi doesn't find will be hers to eat. After a cut, the scene transitions to a conversation over the phone between Koyomi and Tsubasa, who is currently overseas scouting out locations for her trip around the world. Koyomi tells Tsubasa that during the game, he was able to find three of the four donuts, but was puzzled on where the last one could have been hidden. Tsubasa presents the idea that Shinobu hid one of the smaller donuts within a larger one, meaning Koyomi would have eaten the evidence of the remaining donut. Koyomi then asks why Shinobu would do such a thing, as it would go against her intentions of consuming the rest of the donuts. Tsubasa responds, saying that it was Shinobu overlooking her selfish motives and chance of personal gain in order to teach Koyomi, not about secrecy or negotiations, but love.

Yotsugi encounters Koyomi on his way home from the national exams, and asks for his help to search for something. On their hunt, Koyomi discusses his feelings of responsibility to reap the consequences of the seeds he has sown over the past few months.

Late February. Araragi is seen fighting with Yozuru in order to become stronger without the use of his vampire powers as she does. Yozuru tells Araragi that he will die before he becomes able to learn her technique. Araragi then poses the question about Yozuru and Yotsugi seeing as how Yotsugi only calls Yozuru "Onee-san" but is unlike all the males she knows, whom she each calls "Onii-san" after their names. Yozuru then tells Araragi that she'll tell him about their relationship only if he lands a single blow against her in battle. Araragi accepts and goes home. Later, Araragi asks his sister Karen for advice. Karen points out how Araragi should have not accepted the fight at all seeing as how it will be impossible to even land a single blow. She also points out that the extremely hard difficulty only proves how Yozuru does not want to tell Araragi the truth, only indirectly rejecting to answer the question. Karen finishes by saying how she would try to not disgrace her opponent by losing the battle without letting the opponent know that she knows about not being answered at all. Thus Araragi prepares to lose gracefully by getting Shinobu to make him a gun using her vampire power of creation and in turn landing a single "blow" even if it is not a punch. The next day, Araragi goes to the mountain where Yozuru should be waiting for him but she never appears.

March 13, before Araragi is supposed to meet with Senjougahara to go to the university for entrance exams, he goes to the Snake Shrine where he meets Gaen. As Kagenui, Kaiki and Oshino are all missing she feels she has to act. She explains to him how the solution to all the events happening around him would be solved by his death, to which then Gaen proceeds to chop Araragi into small pieces with the original Oddity Killer sword, "Kokoro-Watari". Araragi wakes up in a white void, and is greeted by a familiar face.