High school student Haru Yoshioka is bored with the monotony of life. One day, she saves Prince Lune of the Cat Kingdom from being run over by a truck. As a token of gratitude, the Cat King sends her "presents" and invites her to the Cat Kingdom to become Lune's wife. Haru's inability to properly communicate with the cats leads to the misunderstanding that she has accepted the proposal.

As Haru ponders on ways to escape the predicament, a mysterious voice instructs her to search for the Cat Bureau. However, not long after she finally arrives at the bureau, a horde of cats swarms in and forcibly takes her to the Cat Kingdom, along with a member of the Cat Bureau. Concerned for their safety, owner of the Cat Bureau, Baron Humbert von Gikkingen, follows close behind.

The more Haru immerses herself in the activities of the Cat Kingdom, the more cat-like she becomes. To her dismay, she soon learns that, unless she can find her true self, she may become a cat permanently. Haru's adventures in the world of cats lead her down a path to self-discovery, allowing her to return as a more confident person.

Unaired episode included with the Blu-ray box set.

A peculiar transfer student named Ougi Oshino has just arrived at Naoetsu Private High School. She is quickly introduced to senior student Koyomi Araragi by their mutual friend Kanbaru Suruga, in hopes of obtaining advice regarding a strange discovery she has made. After taking a look at the school's layout, Ougi notices that a classroom has appeared in an otherwise empty area—a place that should not exist. Unsure if this is the work of an apparition, Araragi and Ougi attempt to unravel the truth behind this enigma. But Araragi soon discovers, after finding himself locked in with Ougi, that the room holds the memory of an event he had long since forgotten. [Written by MAL Rewrite]

In an alternate universe, shy, awkward Yuki Nagato attempts to court her crush, Kyon, with the help of her best friend and neighbor, the perky and indomitable Ryoko Asakura. Together, the trio defends their high school literature club from extermination…and from the pestering of their over-the-top classmate Tsuruya and her friend and minion Mikuru. (Source: FUNimation, edited)