Foul Swoops — from left, brothers Devin and Sean Connell, and new drummer Jacky Majic — have reemerged from a long layoff sounding as good as ever. (Photo by Michelle Pena)

Like good luck, dumb love, hot streaks and life itself, rock-and-roll is thrilling and unreliable.

Which helps explain the wild-style inconsistency of Foul Swoops, one of the D.C. area’s best and least-dependable rock groups. Brothers Sean and Devin Connell started this thing back in 2009, and have since put themselves through so many shake-ups, switcheroos and reboots, the personnel adjustments outnumber the songs they’ve released.

But as dysfunctional as things seem to be, everything was functioning like crazy a couple of weekends back at CD Cellar, a record store in Arlington where Foul Swoops was making its first appearance in eight months. The Connell brothers played it grouchy-cool, slashing and droning on their guitars while the group’s new drummer, Jacky Majic, struck his kit as if he were trying to pound giant nails into the carpet.

When it was over, a hypothesis hung in the air: Here’s a band that presents itself with a detached shrug, but actually spends months upon months toiling away in the proverbial basement, anxiously yearning to resurface and detonate. There was a lesson, too: Hurry up and see these guys before they go AWOL again.

Opening for Coup Sauvage & the Snips on Thursday at Logan Fringe Arts Space: Trinidad Theatre, 1358 Florida Ave. NE. Show starts at 9 p.m. 202-737-7230. Free.

[More Music: Garth Brooks shows in Baltimore rescheduled for Jan. 29-31]