When Alexei Ratmansky is not making contemporary ballets, he is reimagining masterpieces like only an artist and advocate could—with loving attention to a world of lost details. For his Paquita “Grand Pas,” after Petipa of The Sleeping Beauty legend, many small pas buzz around the lower leg, with bold, shapey arms making up the difference. The piece possesses French charm and many character types. But the Balanchine + Ratmansky program is mainly taken up with early Balanchine: the Expressionist Prodigal Son, originally for Diaghilev, and Serenade, Balanchine’s first and most enduring ballet made in America. With this neo-Romantic drama to mournful, magisterial Tchaikovsky, Petipa suddenly seems beside the point—a drag on a longed-for ballet future and an avoidance of a deeper past. If you have not seen Serenade, hurry, because once you have, you will be like Balanchine: never done with it. —Apollinaire Scherr