Financially struggling 23-year-old Ah Young cares for her 8-year-old sister Dan Bi while working part-time jobs. 28-year-old Yoo Sang proposes a contractual father-daughter relationship.

Orphan Ah Young is a financially struggling 23 years old who takes care of her 8 years old sister Dan Bi while juggling part-time jobs. One day a 28 years old man Yoo Sang appears in front of Ah Young offering to be her dad through a signed agreement.