One day in 2021, an unidentified skeleton is discovered at a construction site in Gwangju. And 41 years ago, spring is in full bloom in Seoul of 1980. Pro-democracy sentiments run high throughout college campuses, but Hee Tae has no interest in such matters. He is focused on finding enough money to take a patient back home. He returns to his hometown of Gwangju.

Myeong Hee goes on a blind date, pretending to be Soo Ryeon. With Soo Ryeon's coaching on a foolproof way to get rejected on the first date, Myeong Hee expects the date to end quickly. However, whatever stunt Myeong Hee pulls, Hee Tae does something even crazier. The date starts to go in a very unexpected way.

Hee Tae comes to Soo Ryeon's house unannounced, leaving Myeong Hee and Soo Ryeon feeling awkward. Soo Chan, who has no clue about their complicated relationship, asks Myeong Hee to stay for a meal. In Hee Tae's eyes, Soo Chan seems annoyingly friendly with Myeong Hee. Now that the secret is out amongst the three of them, Soo Ryeon, Myeong Hee, and Hee Tae must decide what to do.

Hee Tae suggests to Myeong Hee that they keep seeing each other just for the month of May, but Myeong Hee hesitates to answer him. In order to begin their relationship in earnest, Hee Tae pushes ahead with transferring Seok Chul to Gwangju. Meanwhile, Myeong Hee asks to see Soo Ryeon, but Soo Ryeon gets a mysterious phone call.

After hearing of Soo Ryeon's plight, Myeong Hee decides to put her emotions aside and asks Hee Tae to get engaged to Soo Ryeon. Hee Tae agrees to her request, almost as if he wants to provoke her, and the engagement preparations move along at full speed. Meanwhile, Myeong Hee and Soo Chan run into each other in Seoul.

Hee Tae and Myeong Hee run away from the engagement ceremony hand in hand, and they decide to be true to their feelings. However, a few people witness their escape, resulting in various hurdles and hardships for the couple. Especially, Soo Chan and Ki Nam suspect that something is going on between Hee Tae and Myeong Hee.

Hee Tae goes to Myeong Hee's house in the morning and realizes that she never came home the night before. He wanders around in search of her and eventually ends up at Myeong Hee's home in Naju. Meanwhile, Soo Ryeon finds out that Myeong Hee is facing difficulties with Hwang Ki Nam. She decides to tell Soo Chan her secret.

Hee Tae and Soo Ryeon bid their families goodbye and head to Seoul together. When they arrive at Seoul Station, what awaits them is a protest of 100,000 students and the awkwardness of having to live together. Meanwhile, Soo Chan asks Ki Nam to follow through on the favor Soo Ryeon asked of him. However, Myeong Hee makes up her mind about her plans to go abroad.

Myeong Hee and Hee Tae decide to leave Gwangju as soon as the day breaks. However, as they go about the city and prepare to leave, they realize that things are much different from normal. With injured civilians flooding into the hospital, Myeong Hee refuses to leave her patients. Hee Tae begrudgingly stays to help, despite his bad hunch.

Hee Tae starts to get the hang of things as he continues working in the emergency room with Myeong Hee. However, the situation in Gwangju continues to get worse as the troops open fire on civilians. The couple decides to leave as soon as Mr. Lee comes to take care of Jin A. However, when Mr. Lee arrives at the hospital, he has some unexpected news for Myeong Hee.

As the entire city of Gwangju is put under lockdown by the martial law army, Ki Nam sneaks Hee Tae out of a car crash. When Hee Tae regains consciousness, he finds himself tied up on the floor. Meanwhile, Myeong Hee grows more and more anxious about finding Hee Tae, but Hyun Chul insists that she leave Gwangju with him.

Without any presents or guests, Hee Tae and Myeong Hee marry each other with nothing but a couple of prayers that they wrote. However, their wedding is interrupted by news of Myeong Hee’s father. Meanwhile, the year is 2021, and Hee Tae is a professor of emergency medicine. He gets a message from his brother to meet in person about something important.