BOYS WILL BE GIRLS: David Strattan White (foreground) as Cathy. Cloud 9 is staggeringly ambitious, but loses focus in the second act.

As is so often the case with reunions, mine with Cloud 9 was a mixed bag. Much of the play retains its gleam and gets special polish in Blanka Zizka's snazzy staging. Other aspects, perhaps inevitably, feel dated. What works, works wonderfully. What doesn't—well, doesn't.

Churchill can always be counted on for brilliant theatricality. So the two acts of Cloud 9 exist in two separate-yet-connected worlds. Act 1 finds us eavesdropping in 1890s Africa, where an upper-crusty British family—father Clive, mother Betty, children Edward and Victoria—exists in an uneasy standoff between Victorian order and more primitive instincts.

It's not just the climate that's hot and damp here. The whole group (including assorted friends) find themselves experiencing varying degrees of bisexuality. (Churchill underscores the point by having some characters cross-dress: Betty is played by a man, and young Edward by a woman.)

Cut to Act 2 and London in the 1970s—a world poised uneasily between the swinging '60s and a growing conservatism that will bring in Margaret Thatcher. The family is back (although 80 years have past, Churchill has it that the characters are only 25 years older), carving out new relationships. The casting changes here, with each actor doubling in a different role. As in Act 1 (and in life) identities are fluid, resolutions tentative.

Cloud 9 is staggeringly ambitious, taking on no less than sexuality, feminism, social politics and class, and the British national character. (There's even a fascinating but too-brief excursion into racial tensions.) The play works best in Act 1, as a smashing farce—like Oscar Wilde or Gilbert and Sullivan on LSD. Act 2 is something altogether more realistic and darker—and here's where Cloud 9 feels antiquated.

Anyway, that's how it is in Blanka Zizka's production. All is well in Africa, where the director pulls off some dazzling moments against Mimi Lien's playful scenery (though the sheer vastness of the Wilma stage dilutes some potential comic frenzy). Zizka also gets superb performances from nearly all of her cast (but Kraig Swartz, playing Betty and sounding like Tammy Grimes, introduces too much campy irony).

But the modern London scenes grow maudlin and lose focus, and here the double-casting is also less effective. Amy Fitts, who was a splendid Edward in Act 1, seems far too young for Betty, and only the excellent Judith Lightfoot Clarke is equally good in both worlds.

Still, if we don't quite make it to cloud nine, Churchill's play and the Wilma's production keeps us sufficiently aloft that it's a trip worth taking.

Cloud 9

Through May 28, Wilma Theater, 265 S. Broad St., 215-546-7824.