Chicago: Jason Robert Brown's musical "The Last Five Years" (which just closed after its world premier at Northlight Theatre, though there's talk of a Lincoln Center run) is smart, witty, moving, musically complex and greatly indebted to Stephen Sondheim.  It begins at both ends of a love affair and moves briskly toward the middle, the couple's touching wedding.  Tall, blonde, Irish Kathleen (Lauren Kennedy), an actress never more than ambivalent about her talent and her career, sings her first number more in pain than anger as she prepares to pick up her suitcase and leave the empty New York apartment she shared with her husband.  Next we see the smart, wise-cracking Jewish writer Jamie (Norbert Leo Butz), five years earlier, bursting with testosterone and funny, self-deprecating lines - "struck with the ancient curse of shiksa queens" - as he begins madly falling in love with Kathleen.  Yes, the setup sounds as old as "Abie's Irish Rose," which opened on Broadway in 1922, but don't be misled  Mr. Brown takes this simple idea and triumphs.

Jamie at age 23 gets the beautiful Kathleen to fall in love with him just as he also signs with a top agent, sells his first novel and has first serial rights picked up by The Atlantic.  (There is more than a little autobiography here.  Mr. Brown won a Tony for his musical, "Parade," before he was 30.) But Kathleen's acting career never takes off.  All she gets is one humiliating audition after another (her deconstructed audition song is fabulous) and summer theater somewhere in Ohio.  Midway through the 80-minute piece, they marry and come together for the first and only time for a beautiful duet.  But they immediately come apart again.  Jamie sings "It's A Challenge" as he discovers that all the gorgeous women who wouldn't give him a glance before his success and marriage now want to hop into bed with him.

Mr. Brown was well served by his two performers.  Mr. Butz exuded talent and ambition, couple with a healthy dose of Jewish self-deprecation.  He so convincingly sang Jamie's songs that you believed he wrote the lyrics himself.  Ms. Kennedy's character took awhile to develop, partly because she was working backward in time, but as we learned more about her, she became a poignant and familiar mess of beauty, failure, love, and determination not to be psychologically cannibalized by her larger-than-life husband.

Daisy Prince (daughter of the Broadway legend Hal Prince) directed this complex time warp with precision.  Beowulf Boritt's set, beautifully lit by Chris Binder, craftily revolved the two actors occasionally toward, but more often away from, one another against a backdrop of cliché wedding symbols.  The small orchestra, conducted by Tom Murray, did well by Mr. Brown's challenging music, as it should have with Mr. Brown on the piano.

The only jarring note in the proceedings was the sound.  Both singers were wired.  Northlight is not a huge theater  Is it that producers assume all audiences have been deafened by the decibels of rock music and city living, or that no singers outside of the opera house can belt a song beyond the third row? This is a lovely, intimate musical.  Some day soon, I want to hear these talented singers sing these songs, unadulterated by imperfect theater electronics.  Given the fact that Mr. Brown has created an utterly bewitching little musical, I expect the opportunity will not be long in coming.