Spring 2015. The warm spring sunlight and lush flowers resemble a youth full of vitality. The documentary director captured the youth's 'Mr. Doyoung (22)' on camera. On the highway bus returning to school from hometown, Doyoung accidentally meets his first love, Yonghwa, whom he does not want to see in 10 years. One by one, the memories she doesn't want to recall come back to life. She struggles not to let him know who she is, but it's not as easy as her heart. Will Doyoung be able to overcome this difficult situation well?