You Yongxin, as her name suggests, is an avid swimmer. She is determined to become a national swimmer like her father, You Shan, who was helmed as the "flying fish" in his swimming days. Yet, no matter how hard Yongxin trains, she still underperforms at competitions due to nervousness. Despite numerous failures, the ever-optimistic Yongxin remains steadfast in achieving her dream.
When Yongxin was two years old, her mother walked out on the family. Since then, You Shan became a changed man - he began to lead the life of a conman. Fortunately, You Shan's former teammate, Ou Yingxiong and his wife, Bai Nana, took Yongxin under their wing. The couple has a son, Ou Yaoyang, who is a sailing coach. Yongxin not only idolizes Yaoyang but is also secretly in love with him.
Meeting cellist Wang Yule in a chanced encounter left Yongxin, who knows nothing about music, completely mesmerized by his music. Yule's father was very supportive of his music career but when his father passed away suddenly, he and his mother were plunged into financial difficulties as his mother, Wang Ruoyun, was his father's mistress. They were forced to move into a 3-room HDB flat and thus, became neighbors with Yongxin. Disturbed by Yule's cello practices, You Shan often finds himself at loggerheads with Wang Ruoyun. In spite of her hectic schedule, Yongxin takes time off to help the Wangs with their housework as Yule knows nothing about it.
Fei has just returned from abroad and joins the swimming team. Naturally gifted, Fei chalks up impressive results in the pool, which made Yongxin train herself even harder. Fei's younger brother, Chen Fang, is a sailing enthusiast who trains under Yaoyang. Fei, who thinks highly of herself, finds herself attracted to Yaoyang and takes the initiative to get close to him.
Fei's mother, Yvonne, shows up at the swimming club. She is Yongxin's biological mother who had vanished 20 years ago. After coming into contact with Yongxin, Yvonne developed kindred feeling towards her. When Yongxin realizes that Yvonne is her mother, the latter claims she was abandoned by You Shan. As a result, Yongxin gets the wrong idea about her father. Yingxiong sets the record straight by pointing out that it was Yvonne who walked out on them instead. Troubled by her family background, Yongxin is not able to concentrate on her training. Yule helped Yongxin to get back on her feet by playing the cello for her and staying by her side.
Yule adapts to living in a HDB flat but his girlfriend, Xu Jiayi, feels out of place. Yule's good friend, Thunder, returns from overseas, having made a name for himself as a music conductor. Not wanting to be outshined by Thunder's success, Yule trains even harder. Jiayi gradually finds herself attracted to Thunder as the latter is full of surprises. Seeing how hard his mother works for the family, Yule decided to put aside his pride and performs at a high-class lounge to ease his mother's burden. However, he soon becomes despondent. Yongxin noticed that Yule's cello playing has become emotionally detached. To encourage him, Yongxin reveals that she will always be his devoted listener. Heartened, Yule braces up.
Yule discovers that Jiayi has shifted her affections to another man and that man is none other than Thunder, his good friend. As a result of his inability to accept the truth, Yule loses his hearing temporarily. Yule collapses after being dealt with one blow after another. Yongxin relates her own experience to motivate Yule. Even their parents, You Shan and Wang Ruoyun, put aside their differences to help Yule tide over the crisis.
Yaoyang and Fei developed feelings for each other over time. Yaoyang hopes to have his cake and eat it too by two-timing Fei and Yongxin. Yongxin loses her motivation to swim as she is unable to accept Yaoyang seeing Fei behind her back. You Shan is arrested by the police for fraud again. Mentally and physically exhausted, Yongxin loses her motivation to swim. In the face of her dismal results, Yongxin considers giving up swimming. Seeing how he treats matters of the heart so frivolously, Fei breaks up with Yaoyang, who ends up losing both girls.
Yvonne eyes the plot of land on which the swimming club stands and makes an offer for it. With not a single national swimmer produced after all these years, the board of directors agreed to the sale while Yingxiong and his wife vehemently opposed.
Yvonne sets Yaoyang up, causing him to commit criminal breach of trust. He is forced to convince his parents to support the sale of the land. Deeply hurt by her mother's unscrupulousness, Fei falls out with Yvonne. Yongxin's passion for swimming rekindled and together with Fei, they joined forces to save the swimming club. They made an agreement with the board - the swimming club will not be sold if the swimming club wins the championship title. With Yvonne setting up all kinds of obstacles in their way, will Yongxin and Fei be able to overcome and rise above the challenges to successfully save the swimming club?
Yule finally realized that enjoying the process of learning is the most important aspect of music. Having learnt to let go of the past, Yule becomes more relaxed. At the same time, he receives an invitation from a renowned orchestra and finally attains his goal of being a music conductor. Just as love is blossoming between Yule and Yongxin, Jiayi and Thunder ends their relationship. Jiayi hopes to return to Yule.
As only swimming can help her forget her troubles, Yongxin returns to the pool once again. Fei and Yaoyang bumps into each other, will they be able to re-kindle their romance?