Wicked, in case anyone’s living under a rock, tells the story of the “Wicked” Witch of the West, Elphaba, from her own perspective, focusing on her childhood friendship with the “Good” Witch Glinda. For those of you who’ve read Gregory Maguire’s novel, don’t expect the same intriguing moral ambiguities, complicated characters and dark tone from the show now playing at the Kennedy Center. This is, after all, a musical. The fairly dramatic revisions from the source material, however, fit the medium, as the show does a nice job incorporating its Wizard Of Oz roots with less subtlety, beefs up the friendship between Elphaba and Glinda, and still makes some effort to tackle the whole good versus evil dilemma.

Stephanie Block originated the role of Elphaba when Wicked was being previewed in California, but was replaced by Idina Menzel when the show hit Broadway. It’s hard to understand why. Block invests Elphaba with just the right balance of sarcasm, intellectual inquisitiveness and vulnerability to round her out successfully, and she belts out her signature songs, from the triumphant “Defying Gravity” to the sultry duet “As Long As You’re Mine”, with a powerful self-possession. As Glinda, Kendra Kassebaum is absolutely fearless in her effervescent, obnoxious take on the character, but her tics push your threshold for annoyance, and her voice occasionally veers sharp.

As Fiyero, the center of a love triangle between the two friends and rivals, Derrick Williams can sing and dance with suavity and appeal, but he seems more showman than character. The rest of the cast is largely solid, such as David Garrison as an anticlimactic hustler of a Wizard of Oz, and Carole Shelley as the dangerously meddling Madame Morrible, the head of the girls’ college who rises to political prominence in the second act.