In Richard Linklater’s “Before Sunrise,” Julie Delpy’s Céline suggests that “If there’s any kind of magic in this world, it must be in the attempt of understanding someone, sharing something.” Thirty years after Céline and Ethan Hawke’s Jesse fell in love, Linklater reunites with Hawke for “Blue Moon,” the long-time collaborators’ latest attempt to find that magic. The film in question seeks to understand Lorenz Hart, the great American lyricist who — alongside composer Richard Rodgers — is responsible for countless classics to be found in the great American songbook. But from the outset, Linklater understands the inherent difficulty that comes with capturing such a singular voice all these decades later.

“Blue Moon” opens with two wildly contrasting quotes. One is from Oscar Hammerstein II, who claimed that Hart was “alert and dynamic and fun to be around.” The other is from cabaret legend Mabel Mercer, who describes...