Cardcaptor Sakura (1998) : 1x23

When a rumor starts that a voice is heard in the elementary school music classroom, everyone assumes that it is a ghost singing (much to Sakura's dismay). That evening, Toya comes home with Yukito for a sleepover, much to Sakura's liking. When they arrive home Sakura asks Yukito for tea, and Toya asks, too. When they sit down and talk about the ghost, much to Sakura's dismay yet again, Toya starts on about some of the students hearing the voice some time at ten o'clock in the night. Sakura gets frightened, but then Yukito adds that he heard that the voice was really wonderful, so Sakura decides that she will check it out in case of a Clow Card and to record it. When they get there Sakura is obviously frightened. Then she gets a surprise from Syaoran and Meilin. Suddenly, they hear a voice coming from the music room. They decide to check it out. When they arrive at the music room. Meilin suddenly leaps up and opens the door to the room making the Clow Card disappear. Although Sakura recognizes the song and remembers that it is the song Tomoyo sang to her and will be doing the song for the chorus. They hear it yet again and follow it to the stairs. During the chase, Syaoran and Kero tell the rest that the Clow Card is the Song card.