Théodore, an awkward and humdrum Parisian, discovers the existence of a supernatural song. An old jazz standard from the 1920s that can make two people fall in love instantly, if they listen to it at the same time. His heart skips a beat. He must find that song at all costs and use it to charm Amandine, whom he believes to be the love of his life. His investigation leads him to New York City, where he meets a community of young jazz musicians.