Yin Zixi and Xiujing are college students in the same school, and they both secretly love Shangmin from the Drama Society. Xiujing, who has always been more active and outgoing, asked Yin Zixi to write a love letter to Shangmin. Yin Zixi unreservedly expressed his feelings for Shangmin, but was forced to write Xiujing's name. Shangmin was deeply moved after reading those love letters, but was gradually attracted by Yin Zixi. Yin Zixi felt uncomfortable and even guilty every time he met him, but the more he tried to escape from him, the more fate drew them closer.
Yin Zixi cleaned up the room one day, and accidentally found a mysterious box full of memories of her mother's first love. In the summer of 1968, Jun Ha went to his uncle's house in the countryside to spend his summer vacation. He met Song Zhuxi and fell in love with her at first sight. Song Zhuxi was born in a prominent family, and his family education was very strict. One day Song Zhuxi secretly asked Junhe to show her the haunted house in the village. They had an unforgettable day, but a sudden storm blew their boat away. Song Zhuxi injured his foot again on the way, and Junhe could only carry it on his back. Song Joo-hee walked back around the lake, and it was too late when she sent Song Joo-hee home. Song Joo-hee was sent back to Seoul immediately after breaking out of the disaster, and separated from Jun Ha without saying goodbye. He just hung a string of necklaces around his neck on Jun. On the neck of the river. Jun Ha spent the rest of the summer with a heavy heart.
After the summer vacation, Joon Ha returned to Seoul for class. Tae Soo in the class wants him to write a love letter to a girl, and this girl happens to be Song Zhuxi. Jun Ha did not confess his summer love episode to Tae Soo, but reluctantly obeyed his friend's request. Song Zhuxi and Jun Ha meet again because of Tae Soo, and Jun Ha also uses a street lamp to romantically confess to Song Zhuxi. The two are together. Taesoo tells Jun Ha that he seems to like Song Joo Hee, and confesses to Song Joo Hee. Because of Tae Soo, Tae Soo and Song Joo Hee's parents, Jun Ha and Song Joo Hee are too far apart. Song Zhuxi proposed to break up. But Junhe tried to maintain it. He finally told Tae Soo about his relationship with Song Zhuxi and the story between him. Tae Soo didn't say anything, but just told Jun Ha, don't let his father see the necklace around his neck, because he gave it to Song Zhuxi.
During the winter vacation, the two began to exchange love letters in the name of Taixiu. Unfortunately, one of them was returned to Tae Soo's father. Tae Soo was beaten up by his father. School started again, and Tae Soo hanged himself to perfect the two. Suicide attempted, Song Zhuxi ran into Jun Ha when he went to visit Tae Soo. After speaking to Tae Soo, he found that by the door where Jun Ha was standing, there was only a string of necklaces hanging on the handle. Song Zhuxi rushed downstairs, but saw the army marching. Song Zhuxi participated in the parade and ran into Tae Soo, and the two went to the train station to find Jun Ha. Finally found Jun Ha, but he turned his head and insisted not to look at Song Zhuxi. Finally, the train was about to leave, and he ran to the door, and Song Zhuxi followed the train. He gave the necklace to Jun Ha again.
Junhe participated in the Vietnam War. Once the whole team evacuated under the enemy's bombing, but when he had reached the rescue helicopter, he found that the necklace had fallen on the road. He ran back to find the necklace and rescued a comrade who had fallen behind. Immediately after reaching a safe range, he was blown down by a bomb. The years are fleeting, and the returning Junhe and Song Zhuxi meet in a restaurant. Jun Ha tells Song Zhuxi that he is married. During the conversation, Song Zhuxi was surprised to find that Jun Ha was blind, and tears couldn't help but Jun Ha could not see the tears streaming down Song Zhuxi's face. Junhe ran away in a panic, but fell to the ground. After Song Zhuxi knew that Jun Ha was married, he married Tae Soo and had a daughter, Yin Zixi. Junhe passed away soon, and he told people to let Song Zhuxi scatter his ashes in the river with their memories. And they told Song Zhuxi that Jun Ha actually got married after Song Zhuxi got married and gave birth to a son. Zhu Xi looked into the distance with tears and smiled.
Yin Zixi finished telling the story of her mother. Shangmin on the side couldn't help tears. With red eyes, he took a necklace from his neck—it was the necklace Song Zhuxi gave to Junhe back then. The two laughed.
