Sujeong has amnesia and cannot remember her past and present daily life. The only way out of her memories is the records in her diary. Her boyfriend takes care of her is composed, but waits for her anxiously. One day, Sujeong faces invisible beings, which gradually connects to a case.

A group of mysterious thieves breaks into the office of Cho Seongchi, a famous novelist. The thieves demand Cho Seongchi to open the office’s safe, but Cho Seongchi also struggles to unlock it. As time goes by, the somewhat clumsy thieves are being swayed by Cho Seongchi.