An ordinary student with brown eyes, Ikkyung, and a high school soccer player who resembles the summer sun, Sui. At the age of 18, during that summer, Ikkyung and Sui, who fell into an unexpected love, envisioned a future together and welcomed their twenties. Unlike Ikkyung, who went on to university, Sui entered the workforce directly. Amidst unfamiliar happiness and small misunderstandings, the two will face a new season.