As J’Nai Bridges’s Sister Helen pleads with him to tell the truth, Daniel Okulitch’s death-row convict, Joseph, is slumping onto the floor, recoiling in shame, his handcuffs binding his wrists to a chain cinched around his waist. The singers are rehearsing a beyond-intense scene, showing how the human voice can break out even when the body is in shackles—clearly not the sort of thing Okulitch could achieve if he were pretending to wear the manacles.

“I requested them as early as possible because it affects so much of your physicality and the psychology of the scene,” says Okulitch, a Canadian bass-baritone who has sung the role in Dead Man Walking three times. He’s talking to the Straight in an interview with Bridges after the emotionally draining rehearsal at Vancouver Opera. “You feel so constrained. I mean, we all gesture with our hands, and when you don’t have that ability there’s this energy that has to go somewhere. It’s frustrating! You think, ‘Dammit, I want to move!’ That’s something that prisoners would have to learn to deal with, but I’m not sure that it would ever really go away.”

Adds rising American mezzo-soprano Bridges: “And for sure it affects how I deliver my lines to him, too.”

That physicality, along with the music, plays a huge role in defining the characters in Jake Heggie’s contemporary opera, based on both the 1995 movie and the best-selling nonfiction book by Sister Helen Prejean, with a libretto by acclaimed American playwright Terrence McNally.

“We don’t do a lot of things,” Okulitch explains. “There’s one big action at the beginning in the prologue—the crime—but otherwise it’s people talking to each other in really intense situations. There’s a lot going on! But it’s not ‘Here’s a song and dance and here’s a battle scene.’ It’s an intimate kind of show.”

“It’s really difficult in that way,” adds Bridges. “It’s a big stage that we have to fill with really intense conversations and still let everyone into it. Today I’m really feeling it and I think that’s not a bad thing.…There are some challenges because it sits in this place with my voice that’s kind of speak-y, so I have to be constantly thinking about different things, but one of them is not to get too sing-y—not to get too operatic.”

She’s watched countless videos of Prejean, and read her memoir, trying to unlock the nuances of the relationships that the Louisiana nun had to the prisoners she advised. “There’s a lot of information in the book that you get about how they were physically together, how he would not look at her,” she says. “Details like that have been really helpful.”

In the opera, Joseph (whose name has been changed from Sean Penn’s character Matthew Poncelet) is a composite created from two real-life death-row convicts Prejean befriended in jail. And even though the opera is called Dead Man Walking, the story is really her own—following her discoveries about guilt, forgiveness, redemption, and the death penalty. She is seeing death row for the first time, and through her eyes, we can start to confront how we feel about it, and the capacity to forgive, too.

“One of the phrases we’ve used in rehearsal is ‘It’s a race towards redemption.’ You know, we have a set amount of time, whether or not she can help me be redeemed by opening up about what I did,” the Ottawa-raised Okulitch offers. “We have to remember this is a theatrical portrayal of real-life events. Death-row confessions are rare. They are. But this isn’t a biography. It’s a story about ‘How do you forgive someone and what does that mean?’

“It’s also about the system of capital punishment. But what’s interesting is it doesn’t really choose a side. We know that Sister Helen doesn’t want him to die, but you also get the parents of the victims as major characters in the work saying ‘This was my experience and, yes, we think he should die.’ There’s no question as to his guilt: we see him in the prologue rape and murder someone. So it’s not like you’re saying, ‘Well, did he really do it?’ And then you have the character who plays my mother begging for his life. You see the crime sets off a tsunami of events that destroys the lives of many, many people, and so while it’s not a biography, it’s necessarily operatic. These are huge emotions.”

One of the nuances Okulitch has found, other than the need to wear those metal chains from the get-go, is that he can’t make his character too empathetic or the entire piece loses its power. It’s amazing to watch the affable singer, helped by the score’s southern vernacular, turn into a violent, rage-prone good ol’ boy from the Deep South—one who’s capable of horrific acts.

“The challenge of this piece is that it’s not about ‘Can you forgive somebody who you like?’ ” he emphasizes. “It’s ‘How do you forgive the unforgivable?’

“So the first time I did this role, early on the director said, ‘You’re being way too sympathetic. We have to not like you.’ Because this isn’t about ‘Oh, that poor guy! He’s getting executed.’ He raped and he murdered someone! And he’s unrepentant until the very end.

“The more you humanize someone, the more difficult it is to kill them, that just happens with the writing,” he says, then adds with a laugh: “The whole time I’m not trying to do anything appealing—specifically not, actually!”

The opera, which debuted in 2000, gives a strong contemporary option amid the three big works being staged at the first Vancouver Opera Festival. It complements and contrasts Giuseppe Verdi’s monumental Otello, staged here for the first time in 36 years, and Wolfgang Amadeus Mozart’s classic The Marriage of Figaro. Even though it’s so new, Heggie’s work now ranks as the 21st century’s most produced opera, praised for its rich yet accessible touches of zydeco, jazz, gospel, and rock, and its mix of plainspoken and eloquent text. “In that way it’s a fantastic way for people to get introduced to contemporary opera who otherwise might have misconceptions about it,” Okulitch enthuses, adding that there is still nothing more powerful than the unamplified human voice.

“I love singing in English because I don’t have to think about the emotion. I know what I’m saying. It’s there,” Bridges adds, comparing it to how singing in traditional operatic Italian or French always requires the extra step of translation in her mind.

That emotional immediacy in Dead Man Walking only begins to explain its status as a new operatic classic, directed here by young, fast-rising director Joel Ivany. It continues to succeed, the singers suggest, because it goes beyond the theme of capital punishment into universal struggles.

“The reason it sticks is it’s about the human experience of forgiveness and what is it to forgive someone for doing something unforgivable,” Okulitch says. “So you can have no interest in the death penalty and you can have no knowledge of how it functions; you can not know anyone who’s ever suffered a violent crime and go into this story and still be challenged with ‘What do you have to forgive in your life, what do you bestow on someone?’ ” Then he grabs his iPhone to search for his favourite quote on the subject: “Here it is: ‘Holding onto anger is like drinking poison and expecting the other person to die.’ ”

Dead Man Walking is at the Queen Elizabeth Theatre on April 29 and May 2, 5, and 7 as part of the Vancouver Opera Festival.