Score one for lasting friendships. Susan Cowsill and Vicki Peterson began singing together in the early ’90s, when both were based in Los Angeles; they planned to make a Psycho Sisters album back then, but fate intervened and put them both in the Continental Drifters.

With the Drifters gone, Peterson back in the Bangles and Cowsill settled in New Orleans, they finally got together to make the album last year. The songs are the same ones they were set to record two decades ago, but likely more nuanced than they were back then.

Various members of the extended family help out: Cowsill’s partner Russ Broussard tag-teams on drums with John Cowsill (Susan’s brother and Peterson’s husband); brother Bob Cowsill and ex-Drifters bandmate Peter Holsapple both contribute songs.

But there’s no overshadowing these voices: The duo are natural harmony singers who can embody the magic of ’60s sunshine pop, but give them a haunting melody and they’ll break your heart with it. Most of these tunes are on the darker side, including the ’60s flashbacks that open and close the disc.

Susan first recorded “Heather Says” with the Cowsills at age 10; here, the harmonies and Sam Craft’s violin make the tale of school rivalries sound less cute and more playground-gothic. Harry Nilsson’s “Cuddly Toy,” famously recorded by the Monkees, is reimagined as a cabaret number; Davy Jones danced around the cruelty in the lyric, but Cowsill’s reading is wounded and sympathetic.

There’s a sunnier moment in “Never Never Boys,” with a Byrdsy chiming 12-string, and they get funky and sultry on “Timberline.” But most of these songs are about settling the score with long-ago romantic partners. Peterson’s “This Painting” is a delicious putdown of an ex who leaves some of his crappy artwork as a parting gift; “Numb,” a sinister song about sex, reveals a side of her that’s seldom surfaced in the Bangles. “Fun to Lie” features more 12-string as both Sisters gleefully sing a catalogue of bad pickup lines, but a sweeter bridge shows the hurt feelings underneath.

Maybe they needed 20 years worth of distance to make the songs as gorgeous as they are here.