Ten years have passed since the events of xxxHOLiC Shunmuki. Kimihiro Watanuki, now filled with sadness, has fulfilled his promise to Yuuko by taking over her former shop. He lives with his beloved companions Maru, Moro, and Mokona, while occasional visitors like Shizuka Doumeki, his once-rival turned loyal friend, and former psychic prodigy Kohane Tsuyuri stop by. Kohane studies folklore under Doumeki at university, and together they stumble upon a case that falls perfectly into the shop master's lap. Soon after, Haruka, Doumeki's grandfather, pays Watanuki a visit, asking for his help in investigating Doumeki's dreams. As Watanuki enters the dream world, he witnesses past adventures from Doumeki's perspective, uncovering an age-old truth about the bond between their friends.