Lee Jung-In is a librarian who has been in a 4 year relationship with Kwon Gi-Seok who is a banker and Yoo Ji-ho's senior of the Univ they have graduated. Yoo Ji-ho is a Pharmacist and single dad. After a chance meeting at Ji-ho's pharmacy, they start seeing love and relationships in a new light.^[3]

Lee Jung-In meets Yoo Ji-Ho at the pharmacy when she goes there to remedy her hangover. She tells him she is in a rush and he opens the products and gives them to her before she pays. After drinking, she realizes she has left her wallet at her friend's place. He tells her to just go and pay him back later, along with giving her money for a taxi. They exchange numbers and after showing her his kindness, she cannot stop thinking about him even though she is in a long-term relationship with Kwon Gi-Seok. Gi-Seok and Jung-In's parents have been pressuring her to get married even though she is not ready. After meeting Ji-Ho, she feels even more doubtful about marrying Gi-Seok.

Ji-Ho becomes interested in Jung-In after their first meeting, and intentionally does not respond to her texts so that she will come to pay him back instead of wiring him money. When she finally revisits the pharmacy, he implies his interest in her to which she responds that she could only be friends with him. Later on, they run into each other since Gi-Seok plays basketball with Ji-Ho. She also discovers that Ji-Ho has a child and is a single parent.

Tension builds between the two, as Ji-Ho cannot deny his feelings for her yet she tells him she is uninterested. This contradicts her actions, for there are times that she calls him and wants to meet with him for no apparent reason. Jung-In becomes conflicted with her feelings as she realizes that she cannot stop thinking about Ji-Ho. As Gi-Seok keeps pressuring her about marriage, she becomes even more stressed and tells him the truth about why she is so hesitant to marry him: Gi-Seok's parents disapprove of her.