Season 1

Han Jun-hee continues to grieve Koo Yeon-jun. When she receives mysterious flowers on her birthday, she has an odd feeling that her late lover may be nearby.

While investigating her lookalike, Jun-hee receives a strange package. Kwon Min-ju develops a friendship with her crush but soon faces a huge letdown.

Jun-hee tries to make sense of Min-ju's recollections that get jumbled up with her own. Nam Si-heon discovers a new side to Min-ju.

As Jun-hee struggles to distinguish reality from her dreams, she receives an old diary that contains a shocking truth.

Back in 1998, Jun-hee's bubbly personality shines through Min-ju. Those around her begin to notice — including a mysterious figure who watches from afar.

Si-heon finds himself attracted to the new Min-ju. The love triangle grows when he decides to come clean to Jung In-gyu.

Jun-hee tries to warn the boys of the approaching danger. Meanwhile, a horrifying event takes place at school during the night.

Yeon-jun eventually finds his way to Jun-hee. He does whatever he can to enchant her, but falling in love is not as easy as it seems.

Jun-hee and Yeon-jun enjoy a stretch of happiness. Meanwhile, Si-heon deals with one obstacle after another.

Jun-hee vows to change the past and save Min-ju. Si-heon, while investigating the murder, stumbles upon a chilling truth.

Min-ju turns a blind eye to the dangers ahead and focuses on spending time with Si-heon. Si-heon and In-gyu, however, start to grow suspicious.

As Min-ju takes her life into her own hands, Jun-hee makes a last-ditch effort. She and Si-heon later decide to finally make things right.