Oh Hyunjin, the youngest director of a major drug store franchise, is a workaholic who maintains her hours despite her pregnancy. One day, during an important meeting with a buyer, her water suddenly breaks.

Hyunjin finds it difficult to befriend other mothers and cope with the idea of motherhood. Her supportive husband, Doyoon, meets and seeks the advice of Junseok, a father of multiple children.

Hyunjin is disappointed by her inability to adapt to the role of a good mother. A new mother named Luda, who is considered a troublemaker by the other mothers, takes an interest in Hyunjin.

Hyunjin learns the true nature of the breast milk thief. Later, Hyunjin cannot help but feel jealous of Doyoon's good looks. Meanwhile, Eunjeong is troubled by her rowdy twins' sudden visit.

Hyunjin starts to think that her charms have diminished since giving birth. Eunjeong celebrates her birthday by dressing up and taking the day off. Meanwhile, a shabby-looking man appears at the care center.

Hyunjin's competitor at work, Alex, visits the care center, intensifying Hyunjin's desire to end her maternity leave. After hearing about the master nanny, Hyunjin and Eunjeong contend against each other at the interview.