After an exciting and momentous cultural festival, Shouko Komi continues her endeavor to make one hundred friends alongside her friend and classmate Hitohito Tadano. As winter begins, the class is joined by the seemingly delinquent student Makoto Katai, who has been absent since the first week of school. Despite his intimidating appearance, Katai has difficulty communicating with others and just wants to befriend his classmates. As new friendships form and current ones deepen, Komi and Tadano’s relationship begins to change—though not necessarily for the worse.

Hundreds of years ago, the Chinese zodiac spirits and their god swore to stay together eternally. United by this promise, the possessed members of the Souma family shall always return to each other under any circumstances. Yet, when these bonds shackle them from freedom, it becomes an undesirable burden—a curse. As head of the clan, Akito is convinced that he shares a special connection with the other Soumas. While he desperately clings to this fantasy, the rest of the family remains isolated and suppressed by the fear of punishment. Tooru Honda, who has grown attached to the Soumas, is determined to break the chains that bind them. Her companionship with the family and her friends encourages her to move forward with lifting the curse. However, due to confounding revelations, she struggles to find the tenacity to continue her endeavors. With time slowly withering away, Tooru contends with an uncertain future in hopes of reaching the tranquility that may lie beyond all this commotion.

Now that Koyomi Araragi and Hitagi Senjougahara have graduated, very few familiar faces remain at Naoetsu Private High School. One of these is Suruga Kanbaru, holder of the Monkey's Paw. When she begins to hear talk of a mysterious being known as the Devil who will magically solve any problem, Kanbaru immediately thinks these rumors are about her and decides to investigate. She discovers the Devil is actually Rouka Numachi, a former basketball rival from junior high who is no longer able to play due to a leg injury. Rouka provides free advice to those who seek her out. Acting as a collector of misfortune, she enjoys relieving the stress of her clients by providing them with the false hope of having their problems solved. Although Kanbaru sees no real harm being done, she reprimands Rouka for lying and heads home, relieved she is not the cause of the rumors. But she may have a reason to worry after all: she finds that her left hand has reverted back to its human form.

Within the domed city of Romdo lies one of the last human civilizations on Earth. Thousands of years ago, a global ecological catastrophe doomed the planet; now, life outside these domes is virtually impossible. To expedite mankind's recovery, AutoReivs, humanoid-like robots, have been created to assist people in their day-to-day lives. However, AutoReivs have begun contracting an enigmatic disease called the Cogito Virus, which grants them self-awareness. Re-l Mayer, the granddaughter of Romdo's ruler, is assigned to investigate this phenomenon alongside her AutoReiv partner, Iggy. But what begins as a routine investigation quickly spirals into a conspiracy as Re-l is confronted by humanity's darkest sins. Elsewhere in Romdo, an AutoReiv specialist by the name of Vincent Law must also face his demons when surreal events begin occurring around him. Re-l, Iggy, Vincent, and the child AutoReiv named Pino will form an unlikely faction as they struggle to uncover Romdo's mysteries and discover the true purpose of the mythical beings called Proxies.