In the early days of the 20th Century, American musicals did not have much of a plot. The book was simply a framework for the music, and the songs (generally about love), were interchangeable.

“Rock of Ages,” in a Munopco Music Theatre production at Scottish Rite Cathedral, Allentown, is a throwback to that era, even while it features rock songs from the 1980s.

Using a tongue-in-cheek approach, this jukebox musical does not try to hide the fact that its story is paper thin. It often breaks the fourth wall, with actors speaking directly to the audience, and it has a narrator (Katy Hartzell) who weaves in and out through the onstage action.

All that a show like this really needs is great singing, which the cast of more than 20 amply supplies.

The set includes an elevated walkway and features films of crowds and photographs of buildings and signs at the back of the stage. Along with the re-creation of the “Bourbon Room” at the side of the stage, it effectively reproduces the feeling of Hollywood Sunset Strip 1980s’ decadence.

MunOpCo, not generally known for its recreation of sleaze, does it here with its punk-influenced costumes and attitude.

As the narrator reminds the audience on Sept. 28 opening night, when the performance was seen for this review, every musical needs a love story. In this case, it is between Drew (Anthony Rizzuto) and Sherrie (Jordan Frantz). Drew is (of course) an aspiring musician and Sherrie a would-be actress who has just arrived from Kansas.

Their mutual attraction is upset by Stacee Jaxx (Shannon Cornish). This part was written for a man in the original musical, but the substitution works well here.

Drew winds up being a pizza delivery boy, and Sherrie becomes a stripper in a club owned by Justice (Shy Torres). Things look bad until narrator Lonny tells Drew he is only a character in a musical, and he has to go after Sherrie.

Meanwhile, German developer Hertz Klinemann (Kerry McGuire) convinces the mayor (Cindi Greatsinger) to rebuild Sunset Strip as a clean steet without sex, drugs and rock. This includes the destruction of the Bourbon Room, owned by Dennis Dupree (Jim Hoffman).

He is opposed by city planner Regina (Katie MacMillan) who leads protests on the Strip. In a twist that only happens in musicals, Hertz’s son Franz (Alanna McLaughlin) falls for Regina.

The sound at times makes it a little difficult to understand the dialogue, but it is still pretty easy to follow what is happening onstage.

Throughout the show there are many 1980s’ songs, a number of them rock ballads, including “Cum on Feel the Noize,” “We Built This City,” “Heaven,” “Waiting for a Girl Like You,” “We’re Not Gonna Take It,” “Hit Me With Your Best Shot,” “Every Rose Has Its Thorn,” and a finale of “Don’t Stop Believin.’”

At about two hours and 30 minutes, the show directed by Brenda McGuire is not recommended for anyone who dislikes ‘80s’ rock. But it is fun for just about everyone else.

“Rock of Ages,” 7 p.m. Sept. 28, Oct. 4, 5; 2 p.m. Sept. 29, Oct. 6, Munopco Music Theatre, Scottish Rite Cathedral, 1533 Hamilton St., Allentown. 610-437-2441, https://www.munopco.org/