If it’s hard to slot Kalliope Jones into an obvious genre, it may be because the members were just kids when they started the band. Not college kids or high school students, but Alouette “Lou” Batteau, Wes Chalfant, and Isabella DeHerdt were legit youngsters.

“We started so green and so young that we were able to generate our own musical vision together,” Batteau told the Herald. “We can go into rehearsal now to learn a new song and have a full arrangement after just playing it a couple times. That click has come because we have been able to grow our musical inclinations and creativity together.”

Kalliope Jones’ growth started a dozen years ago in Goshen at the Institute for the Musical Arts — a rock camp founded by June Millington of pioneering all-female rock band Fanny. Back then Batteau, Chalfant, and DeHerdt weren’t bound by scenes or styles, but open to explore whatever sounds they liked.

Flash forward to 2024 and the three are still together — Kalliope Jones plays the Burren in Somerville on Dec. 20 — and still genre-less. This is part of what makes recent EP “10:37 in Heaven” so wonderful. “10:37 in Heaven” features three tracks, each written in the distinctive artistic voice of a different member — often the only unifying thread is the three’s harmony vocals, which adds a unique layer of magic to everything the band does.

Chalfant and Batteau are non-binary and Batteau wrote “Playing the Field” to put some “revolutionary anger in our music,” they said. “I wanted a song where we could go all out (on stage) and encourage other people to use the revolutionary rage and love and compassion that comes from this experience.” The track has a serious fury, and also a sharp hook somewhere between pop punk and noise rock.

“I Love This Mess!” also mines pain and existentialism to make triumphant, big-hearted rock ‘n’ roll. “It’s about getting older and knowing we are inheriting a broken system but also the need to find joy,” DeHerdt said of her song.

Chalfant makes no attempt to look on the bright side with “Holy,” a break-your-heart ballad of infinite tenderness that blooms with a crescendo powered by the trio’s huge harmonies. “I took something really sad and then wrote about it in a really sad way,” Chalfant said with a smile. “It’s a little bit of a Wesley curse. It’s a beautiful curse but I love the music I make. But sometimes I’ll come to rehearsal and say, ‘I have another ballad, and it’s in a minor key.’”

The band is both a single entity and three individual artists who met as kids and haven’t stopped growing together. Or haven’t stopped for long. Different schools, schedules, COVID quarantines, jobs, lives, solo projects, side bands, and more have interrupted the flow but each time the three return to each other.

Next up, a new album due in the spring — the band’s first full-length since 2017, back in kid days. If “10:37 in Heaven” is any indication, it will retain a youthful energy while delivering a mature, broad, and brilliant sound.

For tickets and details, visit kalliopejones.com