Recent worthy plays on the Great White Way include "Frozen," about a man who sexually abuses and kills children, and "I Am My Own Wife," which takes up the plight of a transvestite who survives the Nazis only to be compromised by the Communists who take over.

Even the wildest comedy of the season, "Jumpers," obsesses over the existence of God and an unsolved murder.

Nor are Broadway musicals immune to this trend.

The best musical revival, "Assassins," examines the motives of the men and women who tried (and often succeeded at) killing American presidents. Betrayal and racism lurk just below the surface of the best new musical, "Caroline, or Change."

This somber bent might reflect the national mood, but there is still plenty of room for cotton-candy musicals both new ("Wicked," "Bombay Dreams") and old ("Wonderful Town"). Look for all three to tour.

But this might be Broadway's most sobering season in years. Inside is a quick glance at what's new and what's seriously good in New York.

"Assassins," the Stephen Sondheim musical that seemed preposterous off-Broadway in 1992, now demands attention in a vital Roundabout Theatre production (Studio 54, 254 W. 54th St.).

Driven by a carnival-calliope score flavored with "Hail to the Chief," this rogues' roundup ponders the motives of assassins and would-be assassins from John Wilkes Booth to John Hinckley.

Did bad reviews push Booth (an imperial Michael Cerveris) to his sic semper tyrannus moment? Charles Guiteau (the manic Denis O'Hare) just wanted to be James Garfield's ambassador to France. Who knows what was on the minds of Squeaky Fromme and Sara Jane Moore (Mary Catherine Garrison and Becky Ann Baker, both deliciously clueless) when they tried doing in Gerald Ford.

The most chilling among many such moments for post-Sept. 11 audiences might be the declaration by Samuel Byck (an intense Mario Cantone) that he is going to "drop a 747 on the White House and incinerate Dick Nixon."

The superb cast includes the sweet-voiced Neil Patrick Harris as both narrator and Lee Harvey Oswald. Robert Brill's roller- coaster set, made of railroad ties, soars ever upward.

Director Joe Mantello inventively conceives it as a sideshow shooting gallery (hit the prez, win a prize).

"Everybody's got the right to their dreams," the assassins sing as they aim their guns at the audience. And then they shoot.

There are no gunshots, but history is every bit as dramatic in the small but infinitely involving musical "Caroline, or Change" (Eugene O'Neill Theatre, 230 W. 49th St.).

The word "change" is two- edged, referring both to pocket change and to changes brought about by the civil-rights movement in 1963, the year the musical is set.

Tony Kushner, creator of the expansive, seven-hour "Angels in America," uses a compact 12 scenes in his first Broadway musical to tell a semiautobiographical coming-of-age tale set in New Orleans.

To teach a white, Jewish young man a lesson about the value of money, his stepmother instructs the family's black housekeeper to keep any cash she finds in the boy's pockets at laundry time. When the amount ratchets up from 25 cents to $20, pride and prejudice work their corrosive damage on what was once a close relationship.

This is a beautiful little story told lovingly by Kushner and composer Jeanine Tesori, who allows a wide array of period music to influence her score. Together, they even fashion numbers for the washing machine, the dryer and the moon (each played by a different actor) and the radio (played by a Supremes-like trio featuring Baldwin-Wallace Col lege alumna Tracy Nicole Chapman).

Director George Wolfe keeps the sung-through musical flowing effortlessly from scene to scene. And brooding spitfire Tonya Pinkins leads a superb ensemble cast as Caroline Thibodeaux, the proud and loving housekeeper.

There is hardly a serious mo ment to be had in the truly wonderful revival of "Wonderful Town" (Al Hirschfeld Theatre, 302 W. 45th St.), the 1955 Leonard Bernstein musical about two Ohio siblings discovering the joys of New York.

Working with the orchestra onstage and a minimum of scenery, Kathleen Marshall's sweet, jazzy choreography and smart direction bring us this long-mothballed musical version of "My Sister Eileen" in the freshest form imaginable.

Donna Murphy might not be the best singer, but she more than makes up for it with her side-mouth delivery and limber dancing as writer Eileen. Jennifer Westfeldt is lovely as Eileen's winsome sister, and Gregg Edelman stands tall and witty as Eileen's literary love interest.

The road from Ohio to New York is short compared with the trek from Kansas to Oz in the wildly popular, regularly sold-out "Wicked" (Gershwin Theatre, 222 W. 51st St.).

Going behind the scenes of "The Wizard of Oz" to explore the relationship between Glinda the Good Witch of the North and the Wicked Witch of the West is a great idea for a musical.

But "Wicked" doesn't always live up to the promise of its premise.

Based on Gregory Maguire's 1995 novel, which takes us back to the wizardry-school days of the two witches-in-making, "Wicked" isn't wicked enough.

It relies far too often on its central joke: Glinda is an airhead who does nasty things to remain popular, and the Wicked Witch got a bum rap because her skin is green.

The Stephen Schwartz score evaporates from the brain as soon as you leave your seat. Director Joe Mantello has a keen sense of what makes good theater, but the show's special effects tend to overshadow his work.

Which leaves the performances of pixie-ish Kristin Chenoweth, who uses "cute" as a cudgel as Glinda, and the sharply angular Idina Menzel as the not-so- Wicked Witch. Both are brilliant, even when "Wicked" labors to be funny.

Little is magical about the big new revival of "Fiddler on the Roof" (Minskoff Theatre, 200 W. 45th St.).

That's surprising, given the track record of David Leveaux. He's one of the most inventive directors working nowadays, whether he's doing a big musical (last season's "Nine," for example) or an intellectually challenging play (this season's "Jumpers").

True to form, Leveaux fills "Fiddler" with whimsical flourishes. The orchestra becomes part of the 1905 Russian village of Anatevka, for example, and the czar's soldiers enter the scene from a fairy-tale forest just offstage.

Yet despite strong performances by Alfred Molina as poor, put-upon milkman Tevye and Randy Graff as his long-suffering wife, Golde, this "Fiddler" feels slick and lifeless.

The same is largely true of "Bombay Dreams" (Broadway Theatre, Broadway and 51st Street). Produced by Andrew Lloyd Webber, this $14 million extravaganza is big; it's colorful; it has a spewing fountain that soaks the cast; and it moves (and sometimes grooves) to its own beat.

So why does the rags-to-riches musical, which spoofs cheesy "Bollywood" romance movies from India, leave us so flat? Perhaps because this cliche-driven, bad-joke fest smells more of Vegas than Bombay despite its exotic trappings.

A.R. Rahman's music (which like the rest of the show has been Americanized in its transfer from London) sometimes sets the toe to tapping (especially in "Shakalaka Baby"). Anthony Van Laast and Farah Khan's choreography is fresh and energetic. Mark Thompson's neon scenery and costumes dazzle. And the talented cast works tirelessly.

But the attempted parody of Bollywood remains forever predictable.