A recap episode retalling the events of Bakemonogatari's Tsubasa Cat and the entirety of Nisemonogatari, narrated by Koyomi. During the summer vacation after all the apparition-related incidents around the five girls have been resolved, Koyomi Araragi's two risky younger sisters – the self-proclaimed heroes of justice, Karen and Tsukihi – become involved in some trouble.

Koyomi Araragi and Shinobu Oshino discuss the true nature of Shikigami doll Yotsugi Ononoki, and Koyomi is being rudely woken up by his sisters who tell him to cram for his upcoming college entrance exams.

Koyomi Araragi sees that he has no reflection, and discusses this with Shinobu. She then suggests that Koyomi should see Yozuru Kagenui and Yotsugi Ononoki.

When Yotsugi tells Koyomi that he is indeed becoming a vampire, Koyomi reasons that using his vampiric powers must have come with a price. Yozuru tells him that while there is no way to undo the progress of his transformation, there is a way he can stop it from progressing further: he must no longer use his powers as a vampire. However, this turns out to be quite a challenge when he learns his sisters and Suraga have been kidnapped.

Koyomi and Yotsugi land at the base of the mountain, where they are surprisingly met by Ougi Oshino. She talks with Koyomi for a while about his current situation and his upcoming confrontation with Teori. Koyomi and Yotsugi begin their journey up the mountain.

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.

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.

When Koyomi gets donuts from Hitagi, Shinobu tries to eat all of the donuts.

When Koyomi asks Yozuru Kagenui about the extent of her relationship with Yotsugi, she challenges him to a fight. But then Yozuru disappears...

Mayoi takes Koyomi to meet Teori, who offers him a way to return to the world of the living. Koyomi is in doubt about accepting his offer, as he believes others like Mayoi are more worthy of reviving than him, until he comes with a surprising decision.

Now fully human again, Koyomi is called by Hitagi for a date, as they spend some time together, Koyomi has a vision of Ougi.

Gaen assembles Koyomi, Shinobu, Mayoi and Yozuru and reveals that Ougi is the responsible for some of the previous ordeals they faced.

To stop Ougi from meddling further, Koyomi has a final confrontation with her.

After being exposed, Ougi is about to be engulfed by the darkness, but Koyomi refuses to give up on her and Meme reappears in the nick of time to save them.

Koyomi attempts to make sense of the mirror world with this world's counterparts of his acquaintances. Later at night, Yotsugi then takes Koyomi to meet yet another person from this world.

Koyomi meets the Shinobu of this world; as they converse, she reveals to him his powerful influence on the mirror world.