After leaving the city behind, Jeongwon returns to his seaside hometown of Samcheonpo. There, he meets Dojin, a runaway college student with a bad first impression and nowhere to go. When Dojin ends up staying at Jeongwon’s house under the pretense of teaching him to swim, the two begin an unexpected cohabitation by the sea. As summer unfolds, their awkward start slowly turns into something tender - like the calm waves that bring them closer each day.