Ten years after the events of xxxHOLiC Shunmuki, a melancholic Kimihiro Watanuki has taken over the shop formerly run by the mysterious Yuuko due to a promise he made to her. His companions Maru, Moro, and Mokona live together with him in relative contentment, and some familiar faces arrive every now and then: former rival turned-steadfast friend Shizuka Doumeki, and the former psychic prodigy Kohane Tsuyuri. While Kohane studies folklore under Doumeki at university, they encounter a case that is perfect for the master of the shop. Eventually, Watanuki receives a visit from Doumeki's grandfather, Haruka. He requests that Watanuki investigates his grandson's dreams. While inside the dream world, he discovers how their past adventures played out from Doumeki's perspective of view, leading Watanuki to discover truths from 10 years ago and secrets about the ties that bind their friendship.

Despite having accomplished a lifelong dream of hers, Ann Halford faces further challenges ahead. Bridget Paige, the daughter of the Paige Workshop's owner, still possesses the wing of Shall Fen Shall, Ann's former fairy companion. In determination to save Shall from the obsessive Bridget, Ann decides to join the Paige Workshop, hoping at the same time to perhaps reunite with her close friend. Having been appointed head of the workshop, Ann becomes entrusted with rebuilding it to its former glory. She quickly discovers that the Paige Workshop has a unique focus on tradition and individuality, and recognizes that she will need to learn about her team and completely revamp the workshop in order to succeed. Motivated by her strong desire to rescue Shall and her obligations as a sugar artisan, Ann wholeheartedly dedicates herself to her new position.

With its flickering streetlights, moldy back alleys, and noisy populace, the Second Kowloon Walled City, despite the squalor of its already-demolished predecessor, evokes a special kind of nostalgia that its residents find endearing. Amidst the walls of this fading yet beloved landscape lives Reiko Kujirai, a 32-year-old realtor deeply in love with her coworker, Hajime Kudou, who is two years her junior. Though they have their differences, the two get along well enough to experience the joys of the walled city together. However, everything starts to fall apart when Kudou, half-asleep, suddenly kisses Kujirai—seemingly reciprocating the feelings she has yet to confess. But when Kudou explains that he had mistaken her for someone else, Kujirai finds herself drawn into a series of events that lead her to a past she cannot remember.

Kunon Gurion is born without sight. Refusing to accept blindness as an unchangeable fate, he devotes himself to water magic. His series of personal experiments quickly reveals his talents, as Kunon's grasp of magic grows at a pace that surpasses even those tasked with teaching him. Through constant trial and invention, he develops methods of perceiving the world that do not rely on ordinary vision, reshaping water into constructs that allow him to navigate his surroundings. His ingenuity and rapid progress soon draw attention beyond his lessons, setting him on a path of discovery that tests the very limits of possibility—as well as of his own body.