Koyomi touching the mirror and finding everything reversed is the show asking its own ending a question it doesn't know how to answer yet. Shaft takes six episodes to give you something you thought you already had, and by the final arc, when Senjougahara speaks for the first time in what feels like forever, you realize the whole thing was built just to earn that moment. If you've lived with these characters this long, the excessive setup stops mattering the second their relationships become the actual story.
On the morning after his high school graduation, Koyomi Araragi stands at his bathroom mirror and senses that his reflection is staring back at him. When he reaches toward the glass, his fingers sink into it, and he is pulled inside. He wakes in a strange world where everything is reversed: Karen is shorter than usual, the normally expressionless Yotsugi Ononoki overflows with emotion, and the ghost girl Mayoi Hachikuji has become a grown woman. Yet not everything is what it appears to be. Araragi struggles to find his way home and to work out the nature of this odd dimension. This supernatural mystery drama is the final part of the Monogatari Series' third season and adapts the Koyomi Reverse arc.