Although “Doctor Who” and “It’s Always Sunny in Philadelphia” don’t have a ton in common — in fact, they’re pretty much polar opposites — the latter show’s season 4 episode, “The Nightman Cometh,” plays out in a structurally similar way to “The Devil’s Chord.” Here, the songs are similarly disconnected from the rest of the cast, but they also don’t feel too directionless because they’re all serving a clear plot purpose. Just as Ruby and the Doctor need to play a song or two to fight Maestro, the Paddy’s Pub gang needs to perform a musical in order to help Charlie woo the Waitress. Charlie gets to be the eccentric maniac who drives the plot here, much like Maestro, although he’s not defeated at the end so much as he’s experienced a mild setback. (Just as magical beings related to the toymaker will continue causing chaos, Charlie would continue to creepily stalk the Waitress for a solid ten more seasons.)

Still, it feels like a mistake for “Doctor Who” to let its musical episode follow along the playbooks of sitcoms like “Always Sunny” or “Community,” when the golden blueprints were right there with “Buffy.” The 2002 episode proved that an episodic sci-fi show could have its cake and eat it too, that it could give audiences silly one-off musical performances while also furthering the plot and deepening the characters. When looking at just how much “Once More, With Feeling” accomplished with a similar run-time, it’s hard not to wonder how a more ambitious “The Devil’s Chord” could’ve played out. It’s still a fun, energetic episode with a lot to offer, but it could’ve been so much more. 

New episodes of “Doctor Who” release Fridays at 7pm E.T. on Disney+.