‘Detectorists’ back with existential divining rods

Detectorists and best mates Lance (left, Toby Jones) and Andy (Mackenzie Crook) return for a second season in “Detectorists” on Acorn.tv.

The BBC series “Detectorists” is a mournful comedy, a sneakily funny celebration of futility and stasis. But don’t get the wrong impression. It’s not angsty and serious, in the vein of recent U.S. comedies like “Transparent” or “Togetherness.” It’s as light and joyous as a show about a pair of melancholy British losers can be.

The second six-episode season, available Monday at Acorn.tv, begins with the show’s signature image: Andy and Lance (Mackenzie Crook and Toby Jones) moving slowly across a broad swath of sky and open field. Their insignificance is indicated both by their tiny scale against the Essex landscape and by the metal detectors they carry, the apparatus of the all-absorbing hobby that buffers them from the annoying realities of life — Andy’s timidity and joblessness, Lance’s loneliness and perpetually bruised ego.

There have been changes since season one, though. Nestled at the end of the field is Andy’s 3-month-old baby, the product of his relationship — highly unlikely, objectively, but somehow believable on screen — with Becky, a driven, sarcastic schoolteacher played by Rachael Stirling. (Joining the show in a small part is Stirling’s mother in real life and on screen, Diana Rigg of “The Avengers” and “Game of Thrones.”) And Andy and Lance have moved on to new pastures, literally. Having failed to find the Saxon treasure that we know was buried under the farm they scanned in season one, they’re now failing to find another medieval artifact that’s directly underfoot.

“Detectorists” is a delicate and tricky proposition. If things got just a little out of kilter, funny and poignant could turn to dull and lachrymose pretty quickly. Crook writes and directs every episode, and if he isn’t quite as sharp in the second season — storylines involving Becky’s desire to chuck her job and move to Africa, and a German visitor’s search for the World War II airplane that crashed with his father aboard, are a bit flat — he maintains the show’s morbidly whimsical tone.

He’s helped immeasurably by Jones’ feisty, hilarious performance as Lance, whose diffidence never quite hides his raging pride.

Lance has advice for every situation, and his words to a curious interloper in the new season neatly sum up the show’s worldview: Never touch another man’s detector.