Laura is a fifth-grade student who appears during the main group's summer vacation planning session inside their clubhouse, an abandoned bus. Overhearing their conversation about investigating mysterious sounds and lights on Mount Pinto, she spontaneously invites herself along, revealing her spacey, opportunistic nature. Amy welcomes her presence, relieved to have another girl in the group.

On the mountain expedition, Laura joins activities like exploring tunnels and playing in a pit of sparkling bubbles. Following an interdimensional encounter with the entity Chiki, where an attempt to forcibly reassemble planetary pieces fails, Laura is separated from the group and transported elsewhere. She awakens submerged in water near a floating city. Residents there appear to recognize her upon arrival. Soon after, she encounters a beautiful boy named Ranmaru, who instructs her to board his water glider. Without hesitation, she complies and departs with him.