English title: When We Were Young
Chinese title: 青春最好时
Yin Yin is a popular student at a prestigious high school, but her identical twin Xia Er is living in an orphanage and is being bullied at school. One day, Yin Yin mysteriously disappears. Soon after, Xia Er loses her memories and is mistaken as being Yin Yin. Xia Er then starts living her life as Yin Yin. Can Xia Er discover what happened to the real Yin Yin and why she looks so much like the missing girl—Yin Yin?