The series will explore an alternate universe to the main series, and will focus on Kouji Ibuki, an antagonist in the Cardfight!! Vanguard Movie: Neon Messiah, and Suiko Tatsunagi. (Source: ANN, edited)

Somewhere in the school at noon, one might hear the sound of two girls playing table tennis together as they wait for time to pass by. As if by fate, two students—Sakura Adachi and Hougetsu Shimamura—stumble upon each other on the second floor of the school gymnasium. As they gradually foster a budding friendship, their feelings for one another only become more ambiguous. Growing closer by the day, the two must learn to navigate their contrasting personalities as well as determine the depth of their affection for each other. The nature of this relationship gradually shifts when one of them starts to develop feelings beyond the boundaries of a platonic relationship. Even so, Adachi and Shimamura must realize if forming a bond stronger than friendship will bring them closer or tear them apart. [Written by MAL Rewrite]

10 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. [Written by MAL Rewrite]