Hannah Arendt coined the phrase “banality of evil” when she was covering the trial of bureaucratic Holocaust engineer Adolph Eichmann. But she could have just as easily been describing Comrade Duch, the man who ran the infamous S-21 prison for the Khmer Rouge regime that killed 1.7 million Cambodians in the wake of the Vietnam War. A math teacher in his civilian life, he was, as they say, just following orders.

 In “Cambodian Rock Band,” Lauren Yee’s spirited if disjointed play now running at Alley Theatre (in association with other companies including Berkeley Repertory Theatre), Duch becomes a charismatic, sardonic master of ceremonies, not unlike Joel Grey in “Cabaret.” He wisecracks, he ingratiates, he orders torture, he shows off some dance moves and even plays a bit of cowbell. As played by the lithe, lanky Francis Jue, he’s the life of a rather dark party that incorporates guilt, reconciliation, and, as the title suggests, rock ‘n’ roll.

INTERVIEW: Here's how 'Cambodian Rock Band' came together.

 The play darts back and forth through time but begins in 2008, when we meet Neary (Geena Quintos), a young Cambodian-American NGO worker who has come to Phnom Penh, represented by a collection of quietly sleek neon signs, to help bring Duch (pronounced “Doik”) to justice. She has unearthed previously unseen evidence of a mystery S-21 survivor. Neary is surprised to receive a visit from her father, Chum (Joe Ngo), evasive about his reasons for arriving. (“Cambodian Rock Band” efficiently telegraphs its spoilers, but let’s not do that here).

 But enough about that for now. Bring on the band! Actually you don’t really have to bring it on; the actors are also the musicians, and they excel at both tasks. “Cambodian Rock Band” isn’t really a musical, but the songs, a combination of originals written by the Cambodian American rock band Dengue Fever and vintage Cambodian rock numbers, are a key element of the show’s unique flavor. The stage-within-a-stage pushes toward the audience, which is treated to  a combination of rumbling bass, fuzzy guitar and driving polyrhythms. When you see “Cambodian Rock Band” you get a play and a concert; I kept wishing for a little more volume from the latter.

 The music ends up playing a significant role in the story and its central themes, especially in the superior, hauntingly sparse second act. Here we meet two former bandmates reunited under ghastly circumstances. One is now a prisoner in S-21; the other took the expedient route and now works for Duch, following his orders. Duch also shows up here, forced to face his own humanity through music, including a timely slice of Bob Dylan’s “The Times They Are A-Changin.’” We are reminded that in totalitarian regimes such as this, music generally qualifies as a dissident activity.  

 Cleverly structured as a series of stories within stories, “Cambodian Rock Band” doesn’t always connect all of its dots; the two acts don’t click together so much as they brush against each other. But that’s enough to generate sufficient sparks, especially when things start rocking. By show’s end “Cambodian Rock Band” has become a gloriously raucous affair, as that line between theater and concert is obliterated in a cloud of joy. This might feel like an odd reaction to a show about the Khmer Rouge. But sometimes you just have to go where the music takes you.

Chris Vognar is a Houston-based writer.