A decade after xxxHOLiC Shunmuki, a somber Kimihiro Watanuki fulfills a vow by managing Yuuko's former shop. With Maru, Moro, and Mokona by his side, he finds solace until encounters with old friends like Shizuka Doumeki and Kohane Tsuyuri stir up new mysteries. When Doumeki and Kohane stumble upon an enigmatic case, Watanuki delves into the dream realm at the request of Doumeki's grandfather, Haruka. Inside, he unravels their shared history and unearths the profound bonds that define their friendship.