Sana brings photos from their beach vacation to Junna and Senna's house. Senna excitedly wants to put them in photo albums immediately, and hearing this, Junna believes that if he sees the old photo albums, he may be able to recover his memory. However, Senna claims to have thrown them out by accident, but decides that they should buy one to create memories. At the bookstore, Junna notices Tomo walking by and follows her, but she mysteriously vanishes. While walking home with Senna, Junna still wonders where Tomo went. They encounter a man named Koutarou Ryuuoku, who had participated in a study with the twins' father. He tells them about a dial that their father found at an excavation site, and because the twins were present at the time, he asks them if they remembered anything from it. While Junna tries to remember, Senna tearfully exclaims that she doesn't know anything and retreats to her room.