There was a sense of things coming full circle Saturday at Hill Auditorium for the sold-out second night of the Ann Arbor Folk Festival.

There was Joe Pug, who first became known to Ann Arbor audiences via a well-received one-song cameo at the 2009 festival; since then, he’s become a very popular singer-songwriter and this year returned as the festival’s MC. (Pug will play The Ark on March 9.) There was Mountain Heart, the terrific young bluegrass band that has developed a special affinity for Ann Arbor, even recording a live album here in 2007. And most of all, there was John Prine, headlining the 41st edition of the festival just as he did the very first one back in 1976.

But that’s not to imply that the festival -- which is a fundraiser for Ann Arbor musical institution The Ark -- is stuck in the past. On the contrary, Saturday proved again just how vital, vibrant, and compelling roots-based music can be in 2018 and beyond.

Pug was a congenial MC, helping to keep things moving while offering a number of his own songs in between the featured acts. Songs like “Do My Father’s Drugs,” “Hymn #101,” and “Bright Beginnings” showcased his strong songwriting skills.

The War and Treaty made a huge impression with its fiery opening set. Led by married duo Michael and Tanya Trotter -- and based in both Nashville, Tenn., and Albion, Mich. -- the band lit up the stage with its single “Hi Ho.” Blending gospel, country, R&B, and more, the band features soaring vocal interplay and energetic instrumental work. “I know it’s too loud for you and all, but it’ll be OK,” Michael joked. Full of passion, “Til the Morning” built slowly to a driving peak, bringing the audience to its feet for the first of many times during the show. (The War and Treaty will play The Ark on March 30.)

Brothers Page Burkum and Jack Torrey lead The Cactus Blossoms, who play a classic pop-folk-rock-'n'-roll style. On songs like “Powder Blue” and “Downtown,” their perfectly blended sibling harmonies sounded remarkably like a reinvented Everly Brothers.  (The Cactus Blossoms will play The Ark on April 27.)

Another married duo is the heart of Birds of Chicago. They, too, offered a high-energy musical stew, with Allison Russell’s thrilling, crystalline voice set against JT Nero’s sandpapery growl. Elements of soul, bluegrass, country, and skiffle mixed together in a four-song set that left the audience wanting more, closing with the anthemic sing-along “American Flowers.”  (Birds of Chicago will play The Ark on April 7.)

Next came Mountain Heart, the always-evolving, always-outstanding band whose uniquely fresh take on bluegrass music has made it a favorite of local audiences. And the feeling is mutual: Despite the lack of any direct local connection, leader Josh Shilling called Ann Arbor “our favorite city in the entire country to play.” Mountain Heart introduced an affecting, introspective new song, “Soul Searching,” and closed with the fitting “Miss Me When I’m Gone.” (Mountain Heart will play The Ark on April 20.)

Following an intermission, co-headliner Aimee Mann and her band opened with a couple of older songs, “Fourth of July” and “Little Bombs.” In the middle of the set, 2002’s melancholy “Humpty Dumpty” was a highlight. Overall, though, the songs from her latest album, Mental Illness, really stood out, as well they should. Not 24 hours later the album won the Grammy Award for Best Folk Album. “Patient Zero” is a brilliant reflection on middle age: “Life is grand / but wouldn't you like to have it go as planned?” she sang. Jonathan Coulton, her collaborator on the new album, joined her for three songs. “Rollercoasters” and “Goose Snow Cone” displayed her strong songwriting, but “You Never Loved Me” in particular could have real staying power (and could easily lend itself to covers by other artists in other styles). She closed with two favorites, “Save Me,” from the Magnolia soundtrack, and 1995’s “Long Shot.”

After a somewhat momentum-killing second intermission, John Prine returned to the Folk Festival for a crisp hourlong set. Backed by a lively and talented band, he was in remarkably fine voice. He also freely mixed older and newer material, and while the audience loved it all, the classics generally drew the most enthusiastic responses. He opened with “Love, Love, Love,” from 1986, followed by a pair of songs from 2005, “Glory of True Love” and “Long Monday.” The hits and near-hits included “Your Flag Decal Won’t Get You Into Heaven Anymore,” “Six O’Clock News,” “Souvenirs,” “Hello in There,” and “Angel From Montgomery.” A three-song solo set showcased Prine’s guitar playing, featuring “All the Best” and, of course, “Sam Stone.” Then the band returned for “Please Don’t Bury Me” and the grand finale featuring all the night’s performers -- an extended jam on “Paradise,” a song from Prine’s very first album in 1971. 

Earlier in his set, Prine had introduced a brand new song, from an album expected to come out this spring: “Come on home,” he sang. “You don’t have to be alone; just come on home.” It provided a fitting theme for a memorable night full of terrific music.

Bob Needham is a freelance writer and the former arts & entertainment editor of The Ann Arbor News and AnnArbor.com.

Visit theark.org for information on upcoming shows.