How about KISS?
Love Gun: The Musical! It’s the tragic story of Beth and her boyfriend. They live in Detroit (rock city). He’s in a band that likes to rock and roll all night and party every day. Their love is hotter than hell but they fall into the void so they call Dr Love to try to get back in the New York groove. Show closes with a them singing a duet of “I Will Be There.”
Irving Berlin
Richard & Robert Sherman
Use an opera set from a production of Don Giovanni and you may have theatrical perfection here.
Jim Croce