Robert Plant is the gracefully aging Golden God, the Man Who Won’t Reunite Led Zeppelin, and also the rarest of rock dinosaurs: a 71-year-old who doesn’t look ridiculous in leather pants.

Plant has had a most musically fruitful 21st century, delving deep into Americana on Raising Sand, his 2007 Grammy-sweeping collaboration with Alison Krauss, and Band of Joy, his 2010 hookup with then-partner Patty Griffin.

He’s since got back to his Britishness, relatively speaking, with Lullaby and the Ceaseless Roar in 2014 and Carry Fire in 2017, both recorded with a wildly versatile band he’s called the Sensational Space Shifters.

It was in that mode that Plant returned to the Mann Center on Tuesday night, with a reshaped version of the Space Shifters that now includes Nashville fiddler and guitarist Lillie Mae.

Before Plant and the band took the stage, a video was shown of Swedish teenager Greta Thunberg addressing a United Nations Climate Change Conference in Poland in 2018. “You are stealing our future,” the environmental activist said. Then Link Wray’s “Rumble” rumbled, and the headliner commenced the show with an old song his followers were delighted to hear.

It was “What Is and What Should Never Be,” from Led Zeppelin II. That’s the “you will be mine, by takin’ our time” song, with the wicked descending riff. It was an immediate sign that the singer with the shoulder-length curls and gray goatee — a lion who still roars — was willing to revisit the catalog of the blues-metal band with whom he once so memorably ululated alongside guitarist Jimmy Page.

After brief introductory remarks — “We come from the Old World and … you think you’ve got problems,” he quipped — that’s just what Plant did. Six of the dozen songs played during the enthralling hour-and-a-half set originated in the Led Zeppelin oeuvre.

None, however, sounded exactly like they did in the band’s heyday. Before he found his late career groove with Raising Sand, Plant had called his previous 2005 album — a collaboration with Space Shifters guitarist Justin Adams — The Mighty ReArranger.

Now, with a band that gives him the flexibility to do so, Plant mixes the music up as he pleases, never settling for sitting still. That goes for Led Zep classics like “Black Dog,” transformed into a blues stomp, as well as older songs he has excavated and personalized that have traveled back and forth across the Atlantic, circling around on themselves.

On Lullaby’s “Little Maggie,” a murder ballad born in the British Isles and transported to Appalachia began acoustically, with Liam "Skin” Tyson” on banjo, Lillie Mae (last name: Rische) on fiddle and Adams on a North African oud, before John Baggot’s electronic keyboard added contemporary texture.

Plant talked about how lucky he was to have seen first-generation black bluesmen like Howlin’ Wolf and Skip James in the 1960s before they died, in introducing Bukka White’s “Fixin’ To Die Blues.” And as the song clattered down the tracks, he evoked his heroes Johnny Cash and Elvis Presley in “I hear that lonesome whistle” and “I hear that mystery train” vocal asides.

Robert Plant & the Sensational Space Shifters at the Mann Center for the Performing Arts on Sept. 17, 2019
CHARLES FOX / Staff Photographer
Robert Plant & the Sensational Space Shifters at the Mann Center for the Performing Arts on Sept. 17, 2019

Following one festival performance in Canada, the Mann date was the first show on Plant’s U.S. tour, and the Shape Shifters didn’t always play with the cohesion that comes with time back on the road. I’d love to catch them again on a later date.

In contrast, openers Nathaniel Rateliff & the Night Sweats sounded road tested and truly tight. The show was promoted as a co-headlining bill, and while that might have seemed absurd given Plant’s legendary status, it was clear that the Denver-based beardo Rateliff put plenty of fannies in the seats.

A beefy guy with a burly voice — and the courage to wear white after Labor Day — Rateliff is a light-on-his-feet bandleader who gets things moving with the slip-sliding dancer moves and an eight-piece band ready to take off their hats and get the crowd to sing along.

Rateliff is part of a retro-soul Americana movement that also includes acts like Leon Bridges and St. Paul & the Broken Bones.

A former folkie who began playing drums in his Missouri family’s gospel band when he was 7, then picked up a guitar after his father was killed in a car crash while driving to church when Rateliff was 13 — he found his audience when he got busy with old school soul and signed to the revived Stax label for his 2015 Nathaniel Rateliff & the Night Sweats.

Nathaniel Rateliff, center, & the Night Sweats at the Mann Center for the Performing Arts on Sept. 17, 2019.
CHARLES FOX / Staff Photographer
Nathaniel Rateliff, center, & the Night Sweats at the Mann Center for the Performing Arts on Sept. 17, 2019.

His breakout hit from that album, “S.O.B.,” is a seeming contradiction. It’s a soul-gospel shout-along party song that’s feverish with delirium tremens as it recounts a struggle to defeat alcoholism and get clean. (Remember, the band is called the Night Sweats.)

“I’m going to need someone to help me, I’m gonna need somebody’s hand,” is a cry for help, but also works well as a request for audience participation.

As a singer, enunciation is not Rateliff’s strong point, and his music never feels all that original, as it touches on reference points from Van Morrison to Sam & Dave and Jackson Browne.

He’s an effective bandleader, though, and the crowd who would stand throughout Plant’s set were frequently roused to get up out of their seats and dance during Rateliff’s. And many were there principally for him: The couple next to me went wild all throughout Rateliff’s set, then split after checking out just one song by the headliner, some guy who used to be in Led Zeppelin.