“Falsettos” at Actor’s Express. (Photos by Casey Gardner)

Actor’s Express is presenting the charming, moving musical “Falsettos,” with music and lyrics by William Finn and book by Mr. Finn and James Lapine, directed by Freddie Ashley, running through April 28.

“Falsettos” was first conceived as two separate one-act plays, but finally appeared as a full-length sung-through musical on Broadway in 1992. There was a very successful, critically acclaimed revival in 2016. I didn’t see the revival, but I saw the original, and it is one my cherished memories of theatre-going; and I daresay if you see the Express’ version, it will become one of yours.

The setting is New York City, starting in 1979. What’s it about? Well, here’s help from Oprah Winfrey, of all people: I happened to see the cover of her magazine and this quote: “Wanna hear the most beautiful, complicated, perfectly imperfect word I know? Family.” And for our purposes it’s helpful if it’s bonded by that most powerful glue—love.

Let me introduce you to some sweet, flawed, beautiful human beings. There’s Marvin (Craig Waldrip), his 10-year-old son Jason (played by Alex Newberg the night I saw the show; also played by Vinny Montague), his psychiatrist Mendel (Ben Thorpe), and his boyfriend Whizzer (Jordan Dell Harris).

There is Trina (Jessica de Maria), Marvin’s former wife and Jason’s mother. There are next door neighbors Dr. Charlotte (Kandice Arrington) and her partner Cordelia (Kylie Brown). Each character may be a tad comically neurotic, but each is alive on the planet—and the talented actors who play them bring them to vital, colorful life on stage. These actors also sing—extremely well.

Marvin is rather possessive and is annoyed by the younger, handsome Whizzer’s distaste for monogamy. Young Jason thinks Whizzer is dandy and sometimes goes to him for advice instead of his father or mother. Virtually everyone eventually thinks therapy is a good idea; so the likable Mendel finds himself counseling Marvin, Trina, and Whizzer—with the extra added attraction of falling immediately in love with Trina.

This attraction causes minor consternation for all parties concerned, including Jason, who is precociously smart and asks Mendel his intentions concerning his mother. Naturally, Marvin is not thrilled either (a bit possessive, remember?), but everyone eventually bows to the inevitable, including Trina herself.

Speaking of Trina, things start moving a little too fast for her equilibrium, and in “I’m Breaking Down,” a comic ballad, lament, and crie de coeur, she lets us all know she is close to the edge. It’s a show-stopping moment for Ms. De Maria, whose flawless, finely calibrated performance all evening almost steals the show.

There are many very witty, insightful songs to help move us along at a brisk pace, starting with the startlingly funny “Four Jews in a Room Bitching,” sung by Whizzer, Marvin, Mendel, and young Jason, whose mere presence here enhances the humor. The show (being sung-through) is full of songs, and if I were to start listing them, I’d give away too much of the plot.

I’ll mention a few: “I Never Wanted to Love You,” with Marvin, Mendel, Jason, Trina, and Whizzer. Here we have a key element of the show’s premise: human beings plan, but life disposes. We think we’re in charge, but often it seems the Force (or whatever you’d like to call it) is calling the shots. “Father to Son,” with Marvin and Jason, is a touching ending to Act I.

By Act II Trina and Mendel have married and Marvin and Whizzer have (for awhile) split. The tone changes; it 1981 and Dr. Charlotte and her lover Cordelia are new members of the family. The doctor reports that she’s noticed in the hospital that “Something Bad Is Happening.” Whizzer comes down with a mysterious disease; I’m sure I don’t have to tell you what that is.

Marvin and Whizzer are soon reunited; another lovely moment occurs in “What Would I Do,” which Marvin movingly sings to the sleeping Whizzer. Also “Unlikely Lovers” (Marvin, Whizzer, Charlotte, and Cordelia) echoes the sentiment of “I Never Wanted to Love You.”

And there are many jolly numbers like “Jason’s Bar Mitzvah” which pep us up and never let the proceedings get sad or maudlin. It occurs to me that “Falsettos” is such a quicksilver work that I cannot possibly describe its color, vibrancy, and fun. It needs to be experienced.

Obviously there’s a lot of music, and Alli Lingenfelter is the music director; and she and Mr. Ashley and choreographer Sarah Turner Sechelski keep things humming.

There’s a big space directly in front of the audience that doesn’t get used as much as I would like; that’s rather a puzzlement.

I haven’t said enough about the fine cast. There’s a wonderful esprit de corps which only reenforces the notion of family and what it can be: a scintillating, quirky, sometimes messy collection of partners, parents, exes, babies, and best friends—all bonded by love. For this we thank Messrs. Thorpe, Waldrip, Harris, and Newberg—each of whom brings his own personal vibrancy, magnetism, and charm.

And we thank the aforementioned Ms. De Maria, as well as the delightful Ms. Brown and Ms. Arrington.

When I first saw “Falsettos,” I was extremely moved, partly because I had just lost a favorite relative to AIDS. But you know what? After 25 years and counting, this show still works.

For tickets and information, visit actors-express.com.