Jeong-woo moves into a new home and runs into his old rival Ha-neul, who is his neighbor. As her well-being takes a toll, Ha-neul makes a stand at work.

When Jeong-woo's home gets broken into, Ha-neul asks him to stay at her place. After the two share a night of fun, she decides to help him in his trial.

After a trip together, Jeong-woo wonders if he was Ha-neul's first love — until she goes on a blind date. Ha-neul goes on an interview for a faraway job.

Jeong-woo travels far to show up for Ha-neul after her interview — and several heart-to-heart moments force her to ask him how he truly feels.

A run-in with an old classmate leaves Ha-neul feeling jealous. Regardless, she gives Jeong-woo much-needed emotional support, which opens him up.

While Jeong-woo faces a mysterious attack, Ha-neul finds a crucial clue at his home. Jeong-woo encounters someone who may turn the tides of his trial.

After holding hands with Jeong-woo, Ha-neul tries to decipher their relationship status — but her mental health begins to take a toll amid sudden news.

Jeong-woo and Ha-neul navigate life without each other after she pushes him away. Jeong-woo panics as he operates for the first time since his trial.

As Jeong-woo struggles with his trauma, Ha-neul shows up to support him. But after he rejects her help, he discovers what made her break up with him.

As their love blossoms, Ha-neul and Jeong-woo struggle to keep their relationship a secret. Lee Hong-ran bonds with Bin Dae-yeong during his time of need.

While on a nostalgic getaway, Ha-neul and Jeong-woo are joined by Hong-ran and Dae-yeong. Ha-neul confronts Min Kyung-min about a potential foul play.

Jeong-woo, alongside Ha-neul's family, awaits the outcome of her surgery. Later, he learns the full depth of Kyung-min's complicated motives.

Needing an escape, Jeong-woo takes a special trip to Busan with Ha-neul and her family. He later laments as Ha-neul's new job takes her away from him.

Jeong-woo tries to surprise Ha-neul with a gift, but roadblocks keep getting in his way. Soon, they begin their joint operation and complications arise.

While Jeong-woo awaits an answer from Ha-neul, she contemplates an opportunity abroad—and he anguishes over the fate of their relationship.