説明
Hikari & Uta Sisters with Anna 1 – “What’s Behind the Door…?”（18:33）
Anna came over to visit Uta’s home.
While she was playing in Uta’s room, Uta’s big sister called out, “Uta, come here for a moment.”
Some time passed… and then a faint sound—like something being struck—began to echo from far away.
Curious, Anna couldn’t help but step out of the room and follow the sound.
