Cardcaptor Sakura: Clear Card 6

"A Greater Power As Yue confronts Syaoran about the secrets he's been keeping from Sakura, Sakura grows closer to Akiho. In order to help draw her solitary, book-loving friend out of her shell, Sakura invites Akiho over to show her her father's library. But when a powerful, unknown magical force suddenly descends upon the two girls, Sakura discovers that there may be more to her friend than meets the eye…"

Volume 6 of the Cardcaptor Sakura: Clear Card manga series by CLAMP.