Through an old camera in the club's storage room, Gu An saw something that should not exist. She was a shooting star from three years ago named 'Xinghuo.' Why do you stay in the night sky? Why am I the only one who can see you? Gu An, who usually follows the crowd, wants to investigate and take the initiative for the first time in her life. As an observer and 'the most important friend,' Gu An and Xinghuo set on a journey to find the former club members and fulfill their dreams from three years ago. 'It's... been exposed.' 'But, I'm really happy. Thank you, Gu An.'