Se-eun is a janitor who is always the first to arrive at the pool where she works. One day, she runs into an old friend who is now a swimming instructor.

A job seeking dreamer Yong-jun works part-time at his parents' lunch box house. Yeo-reum lives only to support for hearing-impaired swimmer sister. One day, Yong-jun meets Yeo-reum while delivering lunch boxes and falls in love at the first sight. Yeo-reum slowly opens her heart to warm-hearted Yong-jun.