Meet Seon Ji, a lovely aspiring pâtissier with a secret that even she herself is unaware of: She is under a curse that transforms her into an unmanageable she-devil every night. Daytime Seon Ji has no recollection of Nighttime Seon Ji and the latter’s ungracious behavior.

One summer night, Nighttime Seon Ji bumps into her awkward and jobless neighbor Gil Gu in a spectacular fashion. Seizing this opportunity, Seon Ji’s family hires Gil Gu to work the night shift to watch over her.

While crushing hard on Daytime Seon Ji and navigating their bewildering late-night dates, Gil Gu becomes determined to unravel the curse and help both versions of the girl find their own futures.