At the center of June Moon is Fred Stevens, a young aspiring lyricist who journeys from Schenectady to New York City, where he hopes to make a name for himself in the world of song publishing and nightclubs. On the train he meets dental assistant Edna Baker, and the two embark upon a friendship that evolves into love for her and fondness for him. While struggling to become a Tin Pan Alley notable, Fred takes a shine to his composer partner Paul's glamorous, gold-digging sister-in-law Eileen. The two men sell a song to a music publisher and it develops into a hit. Ultimately, revelations about Eileen's true character help return Fred to his senses and Edna, who he realizes he truly loves.