Koyomi Araragi walks up a giant staircase of a school, and spots a girl falling down. He mentions that if he knew what would happen in the future, he would have kept walking, but instead he decides to catch the girl as she falls to the ground, remarking that she feels surprisingly light.
Sometime after school, Araragi is talking with the class president Tsubasa Hanekawa about the strange girl. The president responds that her name is Hitagi Senjogahara. She's in the same class as them, yet she doesn't really participate much in clubs or school activities, so they propose to give her some responsibilities for the upcoming school festival. Araragi then tells her that Oshino wanted to see him. As Araragi exits the room, Senjogahara appears and quickly thrusts a pen inside his mouth and then follows with a stapler in her other hand. She mentions that a mysterious crab somehow cursed(?) her so that she cannot weigh more than 5 kg. Then she threatens to kill him if he tells anyone about her, stapling the inside of his mouth to prove her point before she leaves. Araragi quickly runs after her, yanks out the staple, and then shows her the completely healed wound. For some reason, the girl trusts him after that, revealing that she somehow is able to carry several different writing-related utensils on her body despite wearing only a skirt and blouse.
Araragi and the girl both walk together to see Oshino. Araragi mentions that he was a vampire until Oshino helped him become human, though he still retains some vampire-like qualities such as superhuman healing and an ability to see well in the dark. He suggests that maybe Oshino could help her out as well. They walk into an abandoned building and see a middle-aged man in a t-shirt (Oshino), who then pontificates on the difference in syntax between kani (crab) and kami (god).