The episode opens with a couple of bodies lying in an alley while a cast crowd round them, adopting attitudes of shock, sadness, etc and grouping themselves picturesquely while Puccini's music plays...
Jessica (in the audience with Dennis) begins to narrate the flashback. The story began when... Yes, the plot is operatic and the cast of opera singers are MELOdramatic. Nothing is what it seems.
Thedore Bikel gives a solid performance but I felt Jerry Stiller stood out as the local cop, sending up operatic conventions with jokes about "Count Fettucine".
As someone else comments, though Tosca underscores the action throughout, the cast are dressed in terrible hand-me-down costumes as kings and peasant girls! Maria can't possibly be playing Tosca and there are no other female roles. The tenor role is a revolutionary leader and the time is about 1810. How come Bikel is dressed as a king?
Never mind, enjoy it, and then skip to the one with Kate Mulgrew as a soap opera queen.
We don't see enough of Dennis's SF flat with its view of the bay and decorative elephants' tusks.