This is a story of rivalry and friendship between two young swimmers; a tale of natural talent versus hard work. Talented swimmer Chung is a transfer student. In his new class, 4C, he meets a swim relay team led by Wing. Despite being proficient in all four styles, Wing is frustrated at his team’s losing streak to Class 4A. At his first swimming gala, Chung plans to show off his skills. Unfortunately, he shows his imperfect starting dives and lack of stamina instead. The mistake he makes in his starting dive even causes his team to lose. After the defeat, he decides to quit the relay match. However, after observing Chung’s freestyle performance, Wing starts teaching him techniques in starting dives and racing. Wing aims to beat Class 4A with the same team members, including Chung.
Yeesa has time-traveled through time and space to change her destiny many times, but this time, she wakes up a year later to find herself in a timeline where the people she used to know aren't exactly who they were in the previous timeline. Feeling lost and out of place in life, she tries to find her way back only to encounter different variables this time that might change her destiny once more.