A river of music runs through “The Porch on Windy Hill,” cross-currents of ancient folk tunes rippling alongside streams of Bach and Haydn. Succinctly, accurately billed as “a new play with old music,” the two-hour production at Skokie’s Northlight Theatre is driven by the sonic sprawl of American folk music, a genre with influences as wide as the world itself.

Conceived and directed by Sherry Lutken (with co-writers Lisa Helmi Johanson, Morgan Morse and David M. Lutken), the production has a three-person cast of immensely talented actor/musicians emphatically evoking one of Shakespeare’s most indelible aphorisms: If music be the food of love, play on. Embedded in a roster of tunes that range from “Down in the Valley” to Bach’s Minuets, “The Porch at Windy Hill” becomes a place where the sharpest edges of a years-long family feud are smoothed over and reshaped.

If the familial troubles of Mira (Johanson), her partner Beckett (Morse) and her grandfather Edgar (David M. Lutken) begin with edges jagged enough to draw blood, they end like sea glass, polished into a rough beauty by an eclectic mix of vocals, guitars, violins, banjos and an erhu, the last a Chinese two-string instrument that’s part flute, part violin and makes a wholly unique sound. The story begins when Mira and Beckett show up at the North Carolina home of her long-estranged grandfather Edgar. Beckett is there as a scholar of “comparative ethnography in the American Folk Tradition,” a songcatcher who is passionate about preserving (and performing) music that has been passed down for countless generations.

The two-pronged plot has Beckett exploring the intricate web of global influences that create American folk music (the banjo originated in Africa; “Blackberry Blossom” sounds more than a little reminiscent of Bach’s Minuet in G) while Mira and Edgar fumblingly try to work through his 18-year absence from her life. Edgar, who is white, cut off all communication after Mira’s mother married a Korean man.

The dialogue deftly captures the ephemeral nature of both family and music. When Mira asks what happened to the porch swing where she used to sit and sing with her grandparents, Edgar replies with honesty both harsh and true:

“You never know when’s gonna be the last time you’re gonna see somebody. We should all remember that.”

Mira’s story is measured out between “pickin’ party” sessions. These sessions are exactly what they sound like: A group of string musicians gather to jam, improvise and riff on folk melodies. Among many other gems the trio puts forth (accompanying themselves on banjos, lutes, guitars, ehrus and violins), is a soulful rendition of “Down in the Valley,” its lyrics morphing from pastoral idyll to lonesome plea for human contact: “Send me a letter/Send it by mail/Send it care of/the Birmingham Jail.”

Edgar’s reasons for ghosting his family comes out gradually. His one interaction with Mira’s father involved an odious crack about the Vietnam Tet Offensive followed by a full-throated yell of “Charlie’s coming through!”

Beckett’s interest in Edgar is primarily as a research subject. For Mira, the relationship is obviously more complex, and larded with racist micro-aggressions. For example: Edgar says he can’t be racist because one of his best friends during the Vietnam War was “Asian,” even if the Asian was probably also a spy because he spoke French fluently. Mira responds that many Vietnamese people speak French thanks to decades of French colonialism. “Imperialism does that,” she notes, stone-faced.

The dialogue also delves the politics of civility. At one point, Beckett’s ire gets the best of him and he pops off at Edgar, condemning him for abandoning his granddaughter and daughter. Then, Beckett scolds Mira for not being equally, vocally angry. Her response cuts to toward the heart of Beckett’s cluelessness.

White men, she responds, “are allowed to be angry. People listen to you when you get angry. I have to prove I have a right to be angry before anyone even pays attention.”

It’s a single, piercing sentence that defines Mira’s lifelong policing of her own emotions — except when she takes up her violin and lets loose musically. As on the grade school playground when a classmate uses a slur to brag about his dad shooting people like Mira, she’s been swallowing rage her entire life, that violin one of its sole outlets.

Lutken gets marvelous performances from her three-person cast, and their musical skills are unimpeachable. When the pickin’ parties (sometimes called hootenannies or shindigs or wingdings) get fully cooking, it’s with a joyful noise. Johanson creates a storm of sound on the violin and the erhu, while Lutken’s Edgar makes the banjo strings resonate like a chorale of steel-winged angels. Beckett holds down his part with a guitar that moves from foot-stomping hootenanny to the subtlest of melodic whispers.

As with most families, there’s no tidy happily-ever-after in “The Porch on Windy Hill.” But the power of glorious music to smooth over family fractures is clear. And that music itself is a whole lotta fun.