"We're setting out to change the world," announce the lead characters in the musical world premiere "Interstate."

Lesbian singer and transgender spoken-word artists Adrian and Dash's quest for world domination involves driving more than 4,000 miles across the country, performing shows and making sure their story gets told. That may sound like "take your medicine, it's good for you" but the sunny, accessible "Interstate" decidedly is not that. In fact, as it builds to its rousing finale, I'm hard-pressed to remember a show that felt more welcoming and joyful. ("Interstate" is part of the Jubilee, a national effort to present stories of queer and trans writers.)

Sometimes, when the phrase "their heart is in the right place" is used, it's a diss, an indication that someone meant well but executed poorly. But that's not the case here. It feels like this show's heart is in exactly the right place, a place of inclusion and wide-open arms.

Melissa Li and Kit Yan's show alternates between two main story lines: Adrian and Dash test their friendship on the road as Queer Malady, with Adrian increasingly alarmed to discover that Dash's gender-confirming surgery seems to have included implanting the need to mansplain and talk over her. Meanwhile, a teenager who has renamed himself Henry is discovering the band online, following the progress of the tour as he negotiates his own coming-out as transgender in a small Kentucky town: "It's like you're reaching out to me/Telling me I'm OK," he sings to his virtual hero, Dash.

With a title that alludes to both a journey and inner states, "Interstate" does not turn away from the tough stuff implied by those complex relationships. Adrian and Dash sing "White Eyes," an angry song about privilege. Henry (Sushma Saha, who's a star) makes himself vulnerable by sharing his story and gets misgendered and mistreated as a result. Adrian (powerful-voiced Rose Van Dyne) grapples with whether to go solo. And Dash (Kai Alexander Judd), in the midst of figuring out how to be a man, has to cope with his growing awareness that he may not be the kind of man he'd like to be.

The script tries to pack maybe a bit too much in, but its clarity and simplicity are a big asset, as when Adrian cuts through others' confusion around gender by saying, "People are who they say they are."

Like "Dear Evan Hansen," whose hero is also a boy who retreats into himself because he feels different, "Interstate" balances its tough, modern story with bright, poppy songs. Li's soaring, Broadway-ready melodies seem to reach out and pull us into the show, as if Adrian and Dash are completing their stated mission one audience member at a time. (When Adrian's mother asks whom a poor musician can help, Adrian snaps back, "People like me.")

Can "Interstate" change the world? It's a tall order but, watching it with an audience at Mixed Blood Theatre, I'd bet money that it can change a tiny part of it.