Encircled in ovals of white light, armed with a pair of guitars and as many lacerated hearts, the two sisters spilled some of their shared blood.
The song was "Call It Off," a spare, acoustic breakup tune of papier-mache delicacy, and Tegan and Sara Quinn sang it with the kind of equally sad and steely resolve that tends to characterize those moments when it's clear that you're speaking to someone for the last time.
"Maybe I would have been something you'd be good at," Tegan sighed by way of goodbye to some former, now extinguished flame. "Maybe you would have been something I'd be good at."
As with the relationship in question, the song was over almost as soon as it began, lasting only a little more than two minutes, a lightning bolt of longing quickly flashing itself out of existence.
But as brief as it was, it encapsulated Tegan and Sara's set at the House of Blues on Tuesday succinctly, as the night was defined by bursts of emotion vacuum packed into bittersweet pop songs that pendulum back and forth between the agony of lost love and the weak-in-the-knees giddiness of love found.
The Quinns engage in their own distinct form of sibling revelry, assuaging one another's hurts by examining them in microscopic detail in songs ripe with a candor normally confined to whispers in a trusted confidant's ear.
"I really like to cry," they announced in unison on "The Con," a lyric that could double as a mission statement.
Mainly, though, Tegan and Sara tunes are meant to be shoulders to lean on -- for each other, for whomever.
Therapists are expensive; concert tickets much less so.
And in many ways, Tegan and Sara gigs double as one big group hug.
"I know the world's not fair to you, I've got a cure for its crimes," Tegan promised on "The Cure," a reassuring yet brooding-sounding number that was like a ray of sunlight disguised as a storm cloud.
That song is culled from the sisters' latest disc, "Sainthood," a catchy, cathartic pastiche of hooks and heartache that the band played the majority of on Tuesday.
The album was recorded live in the studio, and true to those origins, the songs seemed to be tailored for the stage.
Lean, punchy and immediate, they took on added force at the House of Blues, from the hard charging "Hell" to the bright-hued piano pop of "Alligator."
Tegan and Sara's catalog contains plenty of tangents, from buzzing electro to stark skeletal folk to near-punk missives, but what unifies everything is the sisters' pristine harmonies, glowing embers that warm their songs.
Tegan and Sara both sing in different, identifiable cadences, but their voices often meet somewhere in the middle and merge into one, interlocking like some kind of vocal handshake.
It adds a measure of buoyancy to even their most downcast songs, and as such, Tegan and Sara's repertoire often seems to radiate an ebullience that sometimes belies its subject matter.
The sisters' onstage presence enhances this.
Welcoming and wide-eyed, they're all smiles and stories between songs.
These two may trade in heavy emotions, but they make light of it all in the same breath.
"Something's so sick about this, my misery's so addictive," Tegan sang on the growling, invigorated "Northshore," but in this case, that sickness proved to be its own cure.
Contact reporter Jason Bracelin at jbracelin@review journal.com or 702-383-0476.