Like main character Josh, playwright Jake Brasch moved home for a year to get sober and reconnected with his grandparents while there.

"We were both sort of in a fog: They were starting to deal with memory issues as I was reclaiming myself and healing from some time in which I wasn't taking care of myself," Brasch recalled. "We were kind of on the same plane."

The play also touches on more broadly relatable issues surrounding aging, such as what Mary Beth Peil, who plays grandmother Irene, called "the dismissal of the wisdom of the elders." In other words, she continued, "You get old, and people stop listening to you." But as Josh realizes he has more in common with his grandparents than he thought, he starts to empathize and listen to them. They can help him heal, he discovers — and that goes both ways.

"Sometimes we can't see ourselves as well as the people who love us can see us," observed Zien.

The title partly refers to a neuroscience concept called "cognitive reserve." In theory, if you have a greater cognitive reserve, your brain is more resilient against diseases like Alzheimer's, so people do things like puzzles, exercising, and eating healthily to build theirs up.

In the play, Josh sees the literal Cherry Creek Reservoir in Denver as a metaphor for his own cognitive reserve and his recovery journey. "That's the big thing he latches on to: 'If only I can fill the reservoir, if only I can have enough to be able to be the person I need to be, maybe I'll be okay,'" Brasch said.

Armbruster called it a "fever dream," while Chip Zien, who plays the grandfather Shrimpy, called it "a psychedelic trip," "a phantasmagoria," and "a fine tossed salad of mental confusion and fun." Whatever you call it, The Reservoir is simultaneously set in the real world of Denver and within Josh's head. And because Josh is in a hazy state of mind, it's not always clear which is which. That's for the audience to decide.

"We're seeing everything through his lens," said Brasch, offering an example: "Is the thing the grandparents are saying to him, is that actually what they're saying? Has he gone on a tangent in his head? What is actually happening versus what I am seeing?"

"This play is so exciting in that it doesn't exist in one world. It ebbs and flows and bleeds and 'pickles,' as Shelley Butler likes to say, in and out of reality," echoed Galvin. "There are no set boundaries, and we all get to dance in the margins."

Even the audience gets in on it a little: Galvin said we're meant to exist in the world of his mind. What would normally be Josh's inner monologue, he delivers to us.

When Galvin said the cast "dances" between fantasy and reality, he meant it literally. Brasch described the play as a "movement piece" and explained that, because the action isn't always literal, the grandparents sometimes stand in for people and things other than themselves, and their physicality changes accordingly. So yes, you can expect the cast's musical theatre icons, like Zien and Peil, to prove they've still got the moves.

Those recommendations came from various members of the cast and creative team. They're are all wildly different TV shows, but they all combine humor with honest, human stories, and many have a touch of absurdity and make use of memory, too.

As Armbruster summed it up, "To have great humor, you have to have real truth." That's true of all those onscreen shows, and it's true of The Reservoir.

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