Three years after her son Yu-xin vanishes, a grief-stricken Li Yun spots him inside a cracked mirror at home and stumbles into an unknown parallel world.
After meeting her double and a boy who looks just like Yu-xin, Li-yun returns from the mirror world to find Jian-cheng planning to sell their house.
Seeing his family's doubles, Jian-cheng finally believes Li Yun. Meanwhile, Wei-zhe plots to take complete control of Jian-cheng's life.
As family tensions boil over, a rift between Wei-zhe and Mei-ling causes An-an to have a seizure. Meanwhile, Li Yun discovers hidden cameras at home.
Once exposed, Wei-zhe catches Li Yun mid-escape and forces her home. Meanwhile, Jian-cheng focuses on getting back as Wei-zhe manipulates the mirror.
When his secret comes to light, Wei-zhe loses Mei-ling's trust. She aids Li Yun to save An-an, while Jian-cheng crosses back as the mirror breaks.