City Ballet Opens Season at David H. Koch Theater A scene in Balanchine's "Serenade" during the opening night of City Ballet's spring season at the David H. Koch Theater at Lincoln Center. The ballets of George Balanchine make the peculiar natural. You and I do not turn out our legs to 180 degrees; you and I do not dance on point. In the stage worlds of his ballets, however, these things become the premise through which music and drama become keener and more intense. Watching, we find our senses changed. The fusion of music and womanhood and academicism is heady stuff. On Tuesday night, City Ballet's spring season began with Balanchine's "Serenade" (1934). The curtain rose on the very peculiar and entirely haunting ritual in which 17 women stand on flat feet and all in unison, following the seemingly secret dictates of the music, work their way through a series of upper-body gestures that develop inexorably into the lower-body rigor of ballet. When this opening sequence starts, their up-and-out gesture - one arm extended with palm flat, eyes following in that direction - seems to address fate. When it ends the whole body is turned out, and they are academic dancers; that is how fate has changed them. In Balanchine such a statement of ballet's quintessence can only occur with women: they are at the heart of his vision. Images of fate and ballet's academic forms keep intersecting throughout "Serenade." We're watching a pure-dance ballet studded with heart-stopping moments. It's easy to see love, loss, heartbreak, death and transcendence here, and yet they're all borne both on the current of the music (Tchaikovsky's "Serenade for Strings") and on the seemingly unstoppable momentum of a ballet company. Affairs of the heart come and go, and so do life and death; but music and ballet just continue. On Tuesday the corps - immeasurably improved in this ballet since a low point four years ago - was the main glory of the performance. Of the individuals there will be more to say as the season proceeds; the main disappointment was the tepid functionalism of the two lead men, Jonathan Stafford and Ask la Cour. A male friend who joined City Ballet as a dancer in the 1970s told me how most of the time Balanchine seemed to notice only the company's women. But in 1978 he made "Kammermusik No. 2," which featured an all-male corps - "and suddenly we did exist!" On Tuesday "Kammermusik No. 2" returned to the City Ballet repertory after a long absence. This was Balanchine's last important experiment with the modernist music of the 20th century. The score is by Hindemith. There are two leading women, who dance chiefly to the piano; the eight men of the corps generally dance to the orchestral music, which is heavily characterized by brass and woodwind. But Balanchine is not absolutely schematic about this arrangement, and the ballerinas" male partners fit into the music in a variety of ways. The women often flex their feet, dance on their heels and lunge their torsos this way and that; their ponytails fly to and fro. The men often move through two-dimensional frieze patterns, with legs and arms squared, and with their knees and elbows bent. Balanchine was revealing the music by his use of contrasting physical textures - as well as with complex rhythms. A central part of the Balanchine experiment was the way that his choreography led his audience into the workings of difficult music. Now that his ballets are well known, we tend to think of that in the past tense. But because "Kammermusik No. 2" has never been a mainstay of the repertory and because its music is unfamiliar, a good revival brings back the whole present-tense excitement of the adventure. Tuesday's excellent revival was led, marvelously, by Sara Mearns and Teresa Reichlen. It was thrilling to see again that Ms. Mearns can be the most riveting dancer in American ballet; her juicy intensity does the heart good. Ms. Reichlen, the taller of the two, dances with a lighter tone; a bright solo she performs to a flute passage is a highlight. A particular feature of the ballet is the closeness with which the female leads work together, moving in closely overlapping patterns that become like angular, fragmented counterparts to the two ballerinas in Balanchine's classic Bach ballet "Concerto Barocco." A friend seeing this piece for the first time remarked that he didn't like the ballet but loved the two women; my reply was that if Ms. Mearns and Ms. Reichlen get under your skin here, you'll find that so have Balanchine and Hindemith. Tuesday's triple bill ended with the "Brahms-Schoenberg Quartet" (1966). Curiously, it was Igor Stravinsky who drew Balanchine's attention to Schoenberg's 1937 orchestral arrangement of Brahms's 1861 first piano quartet. Balanchine always preferred orchestral music for theater dancing; Schoenberg's setting prompted him to a full-company treatment. Each of the music's four movements is led by a different couple, and it's easy at first to feel that these are four separate ballets. What unites them is a late-Romantic brand of chivalrous ardor and a sense that all these scenes belong to the world of mid-19th-century Vienna. The great event of Tuesday's performance was the Intermezzo second movement: Sterling Hyltin, thrillingly partnered by Robert Fairchild, seemed to keep saying "here is my heart" as she plunged and turned in his arms. Megan Fairchild, dancing phrase by phrase as if anxiously ticking off items in an agenda, was out of her depth in the third, Andante, movement, although her partner, Andrew Veyette, danced with strength. Maria Kowroski, with her glorious physique and shy radiance, and the valiant Tyler Angle led the Rondo alla Zingarese finale well, though without fire. Abi Stafford brought a plucky twinkle to the opening Allegro. It's striking how unalike these three ballets are. Because they point in different directions, they not only celebrate Balanchine, but they also prepare us for the many different directions that City Ballet's spring season will take. As with no other ballet company, I feel a City Ballet season to be a voyage of discovery. The City Ballet season continues through June 10 at the David H. Koch Theater, Lincoln Center; (212) 870-5570, nycballet.com.