NO ORDINARY SUNDAY: Maryann Zschau and Christopher Chew in the challenging title song.

The greatest complaint leveled against the greatest composer of musical theater is inaccessibility. Critics label Stephen Sondheim’s works as cold and unemotional, without music or story harmonious enough to produce a genuine connection with an audience. This claim has extended particularly to Sunday in the Park with George, Sondheim’s Pulitzer Prize-winning musical that, through no small coincidence (but with much irony), investigates an artist who struggles with connection. Sunday is admittedly a challenging piece; it is filled with discordant rhythms and features little attempt at a plot. When well executed, though, it remains perhaps the most profoundly satisfying musical ever written, with audiences treated to two exhilarating climaxes: The first resulting from the completion of a masterful piece of art, the second from the completion of an artist’s soul. The engaging new production of Sunday at the Lyric Stage Company of Boston often manages to tap that incredible power of the work and, even if it never truly ascends to the sublime, offers a deeply moving evening of theater that is distinguished by crisp direction and a stellar cast.

Sunday focuses its first act on George Seurat, the impressionist artist who created “A Sunday Afternoon on the Island of La Grand Jatte.” The opening act, set in the 1880s, follows the progress of George’s work, presenting snapshots of the various individuals that provide inspiration for the painting—a baker, a nurse, a boatman, et al. Their appearances are brief, their depth non-existent; they exist to the audience only as they exist to George. Yet George, who skillfully observes his subjects—effortlessly taking them apart and agonizingly putting them back together by painting tiny, meticulous dots on an enormous canvas—cannot use his keen perception to control his own life; he ultimately fails in his relationship with his lover, Dot, who requires more than a lover who “cannot look up from his pad.” The show’s second act takes place a century later and follows the great-grandson of Seurat, a blocked artist with similar interpersonal problems, who seeks, ultimately through his heritage, a deeper inspiration for both art and life.

The cast of a Sondheim show must acclimate themselves to tricky musical phrases as well as an emotional range that stretches from subtle to in-your-face—and the Lyric cast succeeds in bringing Sunday to life with near-uniform excellence.

As Dot, Maryann Zschau easily navigates the vocal difficulties posed by Sondheim’s compositions, especially shining in the titular rapid-fire opening number. If her acting is not ideally nuanced, she never strikes a false note, and her powerful voice and lush tones are a delight. She is even better in act two as Marie, the aged grandmother of the 20th century George, who serenely mesmerizes with “Children and Art,” a simple, almost lullaby-like song, that discusses the only worthwhile things for a person to leave behind.

The supporting players also lend great energy to the production, commanding the stage without upsetting the balance of the show. Particularly noteworthy are Peter A. Carey, comically masterful as a lustful servant, and Beth Gotha, familiar without being a stereotype, as George’s mother.

If it seems the show’s protagonist is absent, that is not accidental, for that is much as it felt in the theater. The one performance that fell flat was the central one. It was not that Christopher Chew’s George lacked thought; portraying George as a sort of savant, an artistic genius with the emotional maturity of a pubescent boy, is an interesting concept—it just doesn’t work, though. Ignoring the fact that a hero who is broadly sketched and less than intelligent is less than engaging, a shlumpy George also doesn’t fit with a character whose artistic style is deliberate, methodical and purposefully experimental—and whose comments are frequently barbed and condescending. Like Zschau, Chew also improves in the second act. While he remains more insecure and less in command of the stage and his world than appropriate, he closes the show with his strongest acting and singing of the evening.

The entire production is benefited by the strong direction of Spiro Vilidous (also the artistic director of Lyric Stage), who knows he’s working in a wonderful space and does everything possible to exploit it. Scenes are well framed, transitions are quick and central themes are highlighted by staging which never lags or feels unnecessarily cluttered.

As the tableau of the La Grande Jatte painting fades for the last time, George reflects, “White. A blank page or canvas. So many possibilities.” Luckily for Boston theatergoers, most of those possibilities have been investigated with loving color and light, in a rewarding production which reminds of the main benefit of putting on good art—it makes a connection.