With 120 students in the cast, about 120 in the orchestra, a revolving stage and a 12-foot barricade, Mt. Lebanon's production of "Les Miserables" brings the high school musical season in the South Hills to a grand close with its run May 7-10.

Based on the 1862 novel by Victor Hugo, the show tracks escaped convict Jean Valjean as he tries to escape his past, just as the French Revolution seems to be sweeping everything away before it. It is the third longest-running show in Broadway history, opening 1987 and closing 2003.

While some schools might hesitate before taking on the Broadway legend fans call "Les Miz," choir director Jason Greenawalt said the award-winning show was an obvious choice for Mt. Lebanon.

"For us, it has to work for our curriculum," he said, referring to the fact that the musical is part of class instruction for the orchestra and both the dance and tech/theater departments. "We can't do just any pop musical." Mr. Greenawalt, 28, lives in Brookline. This is his third year directing Mt. Lebanon's musical.

And "Les Miz'' is no pop musical. It has no spoken dialogue, many featured roles and a difficult, non-stop score for both singers and orchestra. "The orchestra basically plays only two songs," joked Mr. Greenawalt. "Act I and Act II."

Despite the challenges of the show, he said, "it's amazing to see how much the kids have grown to love it."

Mr. Greenawalt pointed out that with a show this size, he has been lucky to have help from his students. He said Ted Bushman, who plays Jean on Thursday and Saturday and Montparnasse on Wed and Friday, played Marius in the recent Pittsburgh Musical Theater production of "Les Miz.''

"He's been growing up in the musicals here," said Mr. Greenawalt. "He's been a big help, assisting with blocking since he knows the show."

Mr. Greenawalt also praised students directors Gina Federico and Amanda Battaglia. "They've been proactive, always foreseeing what needs to be done and doing it."

On Wednesday/Friday, the show features Jeff Tissue as Javert, Sam Viggiano as Marius, Joe Hoskin as Jean, Carol Brown as Cosette, Lily Smith as Eponine, Tomi Obaro as Fantine and Emily Stack as Mme. Thenardier.

On Thursday/Saturday, Alex Anderson is Javert, Luke Bushman as Marius, Katie Butcher as Cosette, Steph Pecora as Eponine, Dami Obaro as Fantine and Shannon Davis as Mme. Thenardier.

Although budget numbers were not available for the show, Mr. Greenawalt said costs are mostly covered by ticket sales, with the help of program ads and a stipend from the school district.

Mr. Greenawalt is assisted by music director Robert Vogel, choreographer CeCe Kapron, set designer Greg Kuhar, costume designer Betty Disque, technical director Matt Runquist and co-producer Michelle Kramer.

"Les Miserables" plays at Mt. Lebanon High School, 155 Cochran Road, Pittsburgh at 7:30 p.m. May 7, 8, 9 and 10. Tickets are $10, $7 students. Call 412-344-2030 and www.mtlsd.org/district/tickets.asp.