Kim Mi-young is a shy, plain office worker who is often taken advantage of by her colleagues. During a vacation in Macau, she spends a night with a stranger – the wealthy CEO Lee Gun. When Mi-young becomes pregnant, they are forced to get married. Despite their very different worlds, an unexpected love develops between them. However, challenges like Lee Gun’s hereditary illness, family conflicts, and the return of his first love put their relationship to the test.