Encores! Off-Center, a summertime offshoot of City Center’s popular Encores! series that focuses on off-Broadway musicals of the past, kicked off its fourth season on Wednesday with an unexpectedly powerful concert revival of the 1978 rarely-seen teen-rock musical “Runaways.”

Written, directed and choreographed by Elizabeth Swados (who passed away in January), it premiered at the Public Theater during producer Joseph Papp’s heyday, right after the premiere of “A Chorus Line,” and it went on to play 274 performances on Broadway.

An experimental revue in which songs alternate with monologues (some of which are in Spanish and sign language), emotionally scarred teens of different backgrounds come forward and share painful memories about the families they fled, their fears about life out on the city streets and their wild fantasies, and daydreams.

Somehow, “Runaways” is not depressing, which it could have been in lesser hands. In fact, it’s enthralling — a fast and furious, poignant and disturbing 80 minutes. The pop-oriented songs are also pretty memorable.

The production is directed by Sam Pinkleton (choreographer of the Broadway-bound “Natasha, Pierre and the Great Comet of 1812”) with the utmost simplicity and without an intermission, around a bare stage that suggests a city construction site and the floor of a crowded drug house. Choreographer Ani Taj lends wild, seemingly spontaneous movement that reflects the characters’ heightened emotional states.

The large, multiethnic cast (comprised mainly of local high school students) is appropriately young and raw, giving an air of powerful authenticity to the material. Among them is Sophia Anne Caruso, who made a striking professional debut a few months ago in the David Bowie musical “Lazarus.” In an eerie, blank-faced monologue, she describes her daily routines as a prostitute under the firm control of her pimp.

It would be a shame for this production to slip away after its short run ends on Saturday. Might the Public Theater consider giving “Runaways” a home again?