The Belgian pop-rock group K’s Choice packed this restaurant/bar/lounge on a recent early Saturday evening, playing an acoustic set in the vein of their recent lo-fi Little Echoes, a companion album to the North Carolina-recorded, full-band Echo Mountain.

The band, originally fronted by core members and brother-sister combo Sarah and Gert Bettens, began in the early 90s and scored a couple of American alternative hits, notably the anti-drug anthem “Not An Addict.” After going through a bunch of band incarnations and a break-up of the group in the mid-2000s, they’ve reformed as a trio, with the siblings enlisting piano player and vocalist R.J. Swinnen into their ranks, starting with this pair of CDs.

Clad in a Dustin Pedroia Red Sox t-shirt and beanie hat, Sarah—along with her two mates—started off with a few songs off of Echo Mountain, with Gert and her on acoustic guitars and Swinnen on keyboards. The reverent three-part harmonies of “Killing Dragons” were affecting, the song mainly anchored by graceful keyboard-playing and light notes on guitar, sometimes feeling like there was no instrumentation at all—save the voices. Next, the title track contained the inviting refrain “Come with me,” reminiscent of K’s Choice’s classic adventurous spirit, especially as voiced on the album Almost Happy, which the group referred to at the time as a call to adventure or of which the members named adventure as a leitmotif.

Following the first song of the night, Sarah acknowledged the recent tragedy of the Boston Marathon bombings, saying “Our thoughts have been and are with you. You are loved.”

“Come Live The Life,” featuring major contributions from keyboardist Swinnen, lead into the K’s Choice oldie and earnest gem “Butterflies Instead,” off of 1998’s Cocoon Crash; Sarah noted this history by saying the song was “from way back, when we had our original hair colors.” Cheers went up in the crowd after the first words and the song was practically tear-jerking on the aching, hushed “alright’s” of the outro, as this precious number benefited from the acoustic treatment—Gert and Swinnen singing along with utmost care to Sarah’s lead vocals.

Gert was playing acoustic guitar surely and steadily, singing as thoughtfully and with as much restraint as when I saw him 11 and nine years ago on tour in the U.S., always straining—not in voice, but in emotion—to capture the essence of each word.

“Sister,” from Ms. Bettens’ first solo album, Scream (2005), was up next, followed by “I Wanna Get Lost,” off of Little Echoes, which included Gert playing the kick drum while strumming a small-size guitar or ukelele. This tune was bright and optimistic, sounding like a Morcheeba song but, again, recalling the wondering, international spirit of this English-singing Belgian trio. Mr. Swinnen concluded it with a bluesy keyboard solo.

“Not An Addict” came next, played with spare guitar (Gert on the half-size axe, again) and keyboards, which was responsible for the majority of the instrumental layers. K’s Choice then dug into the first of several covers on the night, two of which figure on Little Echoes. This one, not on the album, was the Northern Irish group Snow Patrol’s early 2000’s smash “Chasing Cars,” on which this trio’s harmonies were sublime. “If This Isn’t Right,” of the new full-band album, was buoyant and saw Gert and R.J. adding vocal lushness on backing vocalizations, before the band launched into the happy version of their set (a paraphrase of Sarah’s tongue in cheek concert note), which was made up of Radiohead’s introspective ode to isolation “No Surprises.” Ms. Bettens explained they have to play something chipper and cheery before and after this song, “or people just feel like killing themselves.” The harmonies, nevertheless, were hymnal, choir-like and very hushed.

The love-songs of Echo Mountain were on display soon after with “Someone Just Like You” (which Sarah dedicated on the night to a couple of friends/traveling companions/merch people who are a couple) and “I Will Carry You.”

Sarah next revisited her solo career, with the smokey, jazzy, piano-filled track “I Could Do Better Than You,” from 2008’s “Never Say Goodbye.” Another classic K’s Choice song, “If You’re Not Scared,” was sung next, with Gert playing the sitar-like riff on his small guitar that made me nostalgic again for their 2000 release Almost Happy, when they were the toast of Europe (I remember listening to a major French radio station when I was studying abroad in Paris that year and they were broadcasting a live appearance or concert of this group).

The three musicians then exited, with Sarah saying “Stay Boston Strong” beforehand; they would return moments later, the lone female in the group stating “We’ve learned over the years to not waste any time coming back [before the encore].” They immediately brought things back to an intimate place—Ms. Betten’s voice—with the fragile “My Heart,” off of Cocoon Crash.

She then explained the next, cover song (also on Little Echoes) was one she had first sung when she was ten years old, dancing and lip-synching. It was the Pointer Sisters’ “I’m So Excited,” done acoustic-guitar style to rousing effect at the Somerville, Massachusetts dining establishment and club.

Sarah was ready to introduce the last song of the night, when an audience member yelled out a request—“‘Breakfast’!” (which is on the band’s 1993 debut album, The Great Subconscious Club).The frontwoman demurred at first, saying “It’s been too long.” When she left open the possibility of being able to do it if she had the words in front of her, a bemused Ms. Bettens relented as the fan proffered his smart phone with the lyrics pulled up, and she observed that she couldn’t make the same excuses as she used to back in the day.

In short, the song was performed exquisitely, with Gert recalling the guitar parts and providing the backing “Mmm-hmm” to his sister’s verses about being woken up at night as a kid, by their parents having sex in the kitchen. After the song, Sarah comically thanked the audience member for rehashing such an awkward memory for her.

The final song was, as Sarah explained, one track off the soundtrack her band had written for a Belgian documentary about two Belgian explorers going to the Antarctic. “Letting Go” revolved around the fact that love is about doing just that.

And, though I was sad to see another K’s Choice concert end, and these wistful Belgians head off across the U.S., they left plenty of love in their wake.