ONE OF EARTH'S greatest pop-rock songwriters hides in plain sight in Milwaukee, Wisconsin.

Her name is Betsy Heibler, and she's the voice of Sugar Stems and the power source behind most of the band's preternaturally catchy songs.

Sugar Stems aren't a secret. They've released three albums, including the brand-new Only Come Out at Night, their second on Portland-based label Dirtnap Records. They've toured certain sections of the United States (though never the West Coast) and enjoyed some success overseas.

But as is often the case with power-pop prodigies, Sugar Stems' modest profile does not match up to the massive, irresistible hooks that can be found across the new album's 12 killer tracks, including "Haunted," sung by guitarist Drew Fredrichsen.

Even Heibler's coworkers don't know she's in a band. She's a registered nurse in a difficult field and likes to keep work and play separate, even if it makes her feel like she's living a double life.

"I take off to go on tours for the band and I just tell everybody, 'I'm going on vacation!' They have no idea," she says, laughing. "It's a great stress reliever for me, and it's just nice to be able to leave work and leave that part of my life behind."

If there is any justice in the world—and if she even wants such a thing—Sugar Stems would allow Heibler to leave the day job for good. Only Come Out at Night serves up one punchy hit after another, drawing from '60s girl groups, '70s power-pop, '80s new wave, and modern garage rock. It sounds like the Muffs if Kim Shattuck ditched her Ramones influence in favor of the Raspberries, and has earned the band comparisons to classic female-fronted groups like the Go-Go's and the Pretenders.

It's no surprise, then, that Heibler was raised in a musical home, with records and instruments everywhere. She started writing songs as a teen and began playing as a solo acoustic act before forming Sugar Stems nearly seven years ago. Her husband, Jon, plays drums. Bassist Stephanie Swinney Conard and keyboardist Andy Harris round out the lineup.

"I always tell people that I didn't set out, like, 'I'm going to start a power-pop band today.' That's not what I was really trying to do," Heibler says. "I was lucky because I have a lot of really talented musicians for friends who were so, so encouraging of me: 'Betsy, you've got to keep doing this. You've got to keep writing songs. You've got to start a band.'"

Her friends were right. And those of us who get to enjoy Sugar Stems' music aren't the only ones who benefit. Heibler does as well, in more ways than just musically.

"For me, the band is such an awesome outlet to come home after a stressful day," she says, "and play loud music for a few hours. I love it."