(Photo by Adam Vachon)

"The Seven Layers of Bastian Bachman" goes inside the head of a composer dealing with a brain tumor. Several of the actors who inhabit Bastian's various stages of life are above.

(Photo by Adam Zachon)

Mortality, the passage of time, health, art, loss - they are all in "The Seven Layers of Bastian Bachman."

(Photo by Adam Zachon)

Stephen Kass, center, plays Bastian's David Bowie-esque doctor. The show continues through Sunday at the Phoenix Ice House, in downtown Phoenix.

The set-up of a traditional play is age-old, actors perform, and you watch. But with immersive theater, those roles are not so defined. The audience is invited to wander through the piece and maybe even interact with its performers. This approach is popping up in cities across the country, but it is just starting in Phoenix.

“The Seven Layers of Bastian Bachman," running through Sunday at the historic Phoenix Ice House is one of the first shows in town taking on this new theme on. When you arrive at the unassuming warehouse in near downtown, you are greeted as if this were any other play.

Then, immediately, things start to get a little weird. A young woman takes your name and then instructs you to “take some glasses and a mask.” A butler will soon collect you, she says. That butler turns out to be another young woman who insists you to put on what look like safety goggles and a surgical mask. You follow her to a door outside the historic Phoenix Ice House, and get ready to go inside someone’s head.

"Watch your step in your journey through memory,” she cautions you, as you try to figure out how to do just that. Now, you are exploring the mind of Bastian Bachman, known as BB, a composer with a brain tumor. His mindscape is represented by three floors and seven rooms of this huge industrial space.

As you wander up stairs and past concrete walls, you come across scenes running simultaneously. A teacher and protégé fight about composing music in a room littered by vinyl. A mother and daughter argue about something, though it’s not clear what. These are BB’s fragmented memories. You can come and go as you please, but that does not mean these vignettes are easy to watch.

Director Megan Weaver is just fine with that. BB’s experience of the world “is fragmented and is flawed and strange and has weird surreal qualities to it,” she said. “And the fact that the audience has that experience is fitting and intentional.”

The play grew out of a design class at Arizona State University two years ago. Weaver said she and two collaborators combined their interest in neurology, perception and the mind, and Weaver sees immersive theater as a natural way to convey this blend of ideas.

“Rather than it all being delivered in the same format to each individual, the individual experience becomes a huge part of the storytelling,” Weaver explained.

Another huge part of the story? Music. Stephen Kass, known in this show as simple “Dr," he has a booming singing voice and a confident swagger. He plays an untethered, glam-rock version of a physician, complete with deranged nurses as back-up singers. Kass likes this immersive theater thing. He thinks having the audience in his face keeps him on his toes.

“You really have to be honest, because if you’re just totally faking it, just BSing you’re way through this, you’re going to look just awful,” Kass explained. “You’re going to look horrendous, and it’s not going to read."

But it does read and partly because of how personal the actors get. They can pull audience members aside, speak lines directly to them.

As Juliana, BB’s angsty daughter, Jenny Strickland sometimes leads people outside the building and promises to show them a secret. She shows off a childhood hiding place, really just a city sidewalk, as she whispers memories of growing up. Strickland likes these intimate asides.

“Having a moment to speak to another person face to face and just recount a story is refreshing,” Strickland said.

And it is not the type of thing you get with a typical play. Strickland hopes everyone who comes to “Seven Layers” sees that. In her words, the audience gets to “explore theater on their own, individual taste and creates their own story from what we’ve put out in the space.”

To learn more about “The Seven Layers of Bastian Bachman," visit www.seven-layers.weebly.com.