Who Gave Whom a Youth Like Flowers?

Synopsis:

Born to live the life of a maid despite her young lady's status,

she was the daughter of an entrepreneur, but before she could even leave her swaddling clothes, her father went bankrupt and jumped off a building.

She spent several years posing as a young lady in one wealthy family, only to be passed off to another.

The unlucky man who took her in was an elite counterintelligence agent,

so she became a code-breaking girl.