Well, the episode gets right to business; I’ll give it that. Mono-monikered Broadway composer Bluestone is pounding out a new tune on the piano in his swanky Manhattan condo when a man appears. He says, “Who the hell are you, and how did you get in here?” The man compliments the tune, but says Bluestone will never get a chance to see it performed. Bluestone steps through the piano and is horrified to see his body in a sweater-vest; also, because it is on the floor dead.
The man — the Prince of Darkness — says the gang “below-decks” loves his music. What would it take for him to play them a tune now and then? Bluestone says he wants “to make it with Mary Ellen Cosgrove.” He is careful to add about his long-ago crush “as she was.” Let’s hope they didn’t meet in 6th grade.
The man sends Bluestone back in time. Some awkwardness is ironed over by the fact that he puts Bluestone back in his high-school body; and also, for some reason, made him Middle-Eastern. However, it is a little disconcerting that the actor portraying young Bluestone is 24 and the actress portraying Mary Ellen is 15. Not to mention the fact that it is a 52 year old man in the younger dude’s body. 
Bluestone is greeted by his original moniker Binky Blaustein as he enters the party of high schoolers. He realizes that his memories of Mary Ellen are warped, that she is “just a kid”. He spots another girl, the titular Teresa Golowitz. The Devil has now possessed the body of Laura — Gina Gershon, who frankly blows every other girl at this hootenanny off the screen. Binky admits he never paid much attention to Teresa because she was too plain. The Devil reminds Binky that Teresa committed suicide the night of this party. He tells Binky the whole sad story, then says, “Excuse me. Laura has to go to the little girl’s room.” What? Ewwwww . . . That’s creepy even for the devil.
Binky starts talking to Teresa, but is impressed into service by a jock. He says, “You’re a big show-tune man, Blaustein. How about something from Broadway?” Wait, shouldn’t this line have been delivered by a kid the jock later beats up? OK, this scene is set in 1948. Maybe this was normal behavior for high school kids then.
Binky begins playing How About You. Mary Ellen begins singing, but is quickly eclipsed by Teresa emerging from the background to belt out the tune. Binky catches up with her outside and begs her to work with him to develope her talent, thus preventing her suicide. Back in the present, Teresa is now a Broadway star, famous singer, expert on politics, and respected climatologist.
Despite having no physical resemblance to Bluestone, Grant Heslov is excellent as Binky. I didn’t really associate him with the older character, but I completely bought him as a character older and more mature than his physical appearance. Gene Barry as the Devil seemed to play his role a little effeminate for reasons that elude me. The other performances were unexceptional; except Gina Gershon who was exceptional.
-  I’m not good at guessing ethnicities. It is Grant Heslov, who was just in The Outer Limits. He seems to play a lot of Middle Easterners. Also Hispanics. I guess Hollywood isn’t good at ethnicities either.
-  Although not as egregious as the movie Big where a 28 year old woman slept with a 14 year old boy. A offense like that could get her a weekend in jail.