For the cast of "The Mystery of Edwin Drood," a musical premiering tonight at Diamond Head Theatre, the end of every performance really is a mystery — because the audience decides whodunnit.

There are 31 possible conclusions, explained director-choreographer Greg Zane, and the actors had to learn variations of their parts to suit each one.

"In Act II, the viewers decide who the detective is, who the murderer is, and who they want the two lovers to be for a happy ending. And like 31 children, each has a different need."

Thus, there are 175 potential liaisons in playing out the finish, said Suzanne Green, who has the title role (and another, a character named Alice Nutting) in the show. She doesn't have to learn the substitute endings because much of the action surrounds her Drood, but she has to be aware of the variations.

For Green, the production is therapeutic.

"I am a domestic-violence educator for the Hawai'i State Coalition Against Domestic Violence, so playing a male through most of the show sounded like so much fun," said Green. "What's weird is that Drood is a very entitled, pompous character; in the arena of my day work, male entitlements tend to play out in the mindset of men who are domestic perpetrators. So this is my therapy."

Zane, who now lives in Soho in New York City but previously lived in Honolulu, said he was discussing DHT's current season a while back with John Rampage, the theater group's artistic director.

"He had asked for suggestions for the winter slot. I recommended 'Edwin Drood,' figuring some poor fool will direct, and I guess I'm that poor fool," he chuckled.

Zane recalls seeing the Broadway version in 1986, with Donna Murphy in the cast. "Ten years later, unbeknownst to me, she would become my friend when we worked together in 'The King and I,' " he said. "She loves the piece, because it's so much fun."

Guy Merola, who plays John Jasper (plus Clive Paget), said his voice was right for the split-personality role he's tackling. And the time was ripe for him to return to a theatrical role. And yes, it's been much fun.

"I hadn't done a show in five years, and every year, I look at the season offerings to see if there's an interesting part for me," said Merola, who is vice president for finance at Commercial Data Systems Inc.

Jasper is a Jekyll-and-Hyde sort, "and both vocally and dramatically, a challenge to do," he said. "When you do (community) theater, you give three months of your life, so you want to grow from it as a performer."

He hadn't seen a production of "Drood," nor was he familiar with the score, so he did some research.

"As a performer, it's something of a challenge because it's not just a fluff role," said Merola. "I think I'm stretching as I'm learning."

He's thankful that Zane hasn't thrown difficult choreographic turns his way.

"Let's just say he has us all moving, in somewhat easy routines, and not embarrassing a single one of us. I am not a dancer, and he can judge pretty quickly."

Green hopes she's not being typecast by playing a male — again. She portrayed a guy in DHT's 2003 production of "Ragtime."

"It's the music, and especially the camaraderie, in doing a show," she said of her delight in taking on theatrical roles. "You don't make enough money to pay for gas, but you wind up with great friendships, renewing ties and making new friends. I think I know about a third of the people in this show — and there's not a diva in the crowd. All nice folks."

Zane said he knew he found his Jasper in Merola "because he's good, going from the manic psycho to the angelic choirmaster."

And of Green, Zane said, "she's got the style of the old Victorian theater, working well in the very highly stylized play-within-the-play in the show."

When he's in the Big Apple, Zane teaches ballet at the Broadway Dance Center. He's also on the lookout for stage roles, particularly productions that hire Asian actors.

He's thrilled that a next-generation actor, Jason Tam, will play Paul in the fall revival of "A Chorus Line" in New York. Paul was a pivotal role in bridging Zane's own dance and acting careers early on, thanks to his then-mentor, the late Tommy Aguilar, who created the role in the London company and mounted an earlier "Chorus" production here.

"It goes in cycles," said Zane.

Reach Wayne Harada at wharada@honoluluadvertiser.com.