As the melancholic melody coming from a small music box echoes throughout what seems to be an abandoned warehouse, a lonely boy with a messy black hair quivers as he hugs his knees. In that abandoned place filled with nothing but torn boxes, random mechanical parts, and a faint smell of oil, only the music and the boy's cry can be heard, making a lonely yet perfect harmony.

"Reve? Are you there, Reve?" A girl in a white one piece dress asked as she peeks inside the warehouse.

The boy jolted as he heard a call from the only spot where light permeated. With tears on his eyes, he called softly. "Arya?"

"Reve! I have been looking for you!" the girl exclaimed as she runs towards the boy with her long black hair dancing with her every step. "Why are you crying?"

"I was really scared. I suddenly found myself alone in this place, and it's dark, and that music box suddenly started playing, and-"the boy was again crying as he tries to explain himself.

"There, there. Don't cry. Your guardian angel is here. Maya and Drew are waiting down the hill. They are all worried when you suddenly disappeared, you know? Now, let's go back." The girl said, stretching her arm as she flashes a gentle smile, which in turn soothed the boy's frightened heart.

The boy simply nodded and returned another gentle smile. With his shaking hand, the boy softly held the girl's hand as he stood up. After a short hesitation, both of them reached for the exit.

"Arya. I finished it." The boy said as he forces a smile. "I completed our summer adventure."

"What are you talking about?" The girl said gently.

"I made a list of mysteries and you have to solve them." The boy announced, regaining his excitement and energy.

"You came all the way here for that. Silly Reve." The girl laughed it off. "Well, I'll look forward to that. Watch me as I solve every single mystery."

As they were about to leave the warehouse, it made a sudden creaking sound. And before the two kids managed to utter even a single word, they were engulfed in darkness.