Brittany (Heather Morris) and Santana (Naya Rivera) get to know Rory (Damian McGinty).

Glee” returned from its World Series hiatus and picked up right where it left off, shifting more New Directions members (Santana, Britney) into the newly formed all-girl rival show choir group now dubbed The Troubletones; allowing Quinn to nonsensically continue her quest to regain custody of her daughter; and giving Sue Sylvester a new congressional opponent in the form of Kurt Hummel, arts-supportive yet salt-of-the-earth seeker of pubic office. Oh, and it also permitted Puck to hook up with Shelby (Idina Menzel), the adoptive mother of a child that he fathered with a birth mother who tried to call Child Protective Services on that adoptive mother. Got all that?

But the truly important thing that happened during the episode “Pot ‘O Gold” was that Rory Flanagan — the ultra-Irish exchange student played by “Glee Project” winner Damian McGinty — made his debut at McKinley High, proving he has strong vocal skills, as well as a haircut that he apparently got in 1959. Which could work out well, what with McKinley doing “West Side Story” this year and all. (Oh, and yes, in addition to looking a little like a young Fred Savage, McGinty is genuinely Irish).

But enough about all that. Here’s the weekly Celebritology “Glee” recap based entirely on the musical numbers, which, at a total of five, yielded a decent average of one tune per every 12 minutes of “Glee,” commercials included.

Rory: “Bein’ Green”

Since McGinty’s legitimate Irishness may not have fully conveyed amidst all those Lucky Charm, U2 and leprechaun references — not to mention the fact that Rory was perpetually dressed in the colors of the Emerald Isle — the “Glee” team made him perform this Kermit the Frog classic. It was tweaked to become a song about Irish exchange students being bullied. McGinty sang it nicely enough, but the concept felt a wee bit (wow, “wee bit” sounds so Irish!) forced. Although it did tie in nicely with the commercials for “The Muppets.”

P.S. Would any young Irishman, even a meek one, allow himself to be consistently referred to as a leprechaun, even if a pretty girl like Britney S. Pierce (Heather Morris) was the one saying it? I mean, if she had done that to one of those guys from The Commitments, for example, they would have clocked her in the jaw and called her a bunch of curse words she didn’t have a prayer of understanding. Grade: B.

Blaine and company: “Last Friday Night (T.G.I.F.)”

Blaine (Darren Criss) has made himself de facto inspirational coach for the New Directions, a role that previous de facto inspirational coach Finn (Cory Monteith) didn’t appreciate much. To underscore just how inspirational he is, Blaine led the group in this rousing sing-a-long, which incorporated several “Glee” tropes: use of a Katy Perry song, Criss doing his charming white-boy dances and spontaneous harmonizing in the choral room. In other words, we’d seen this routine before. Grade: B-

Puck: “I’ve Been Waiting for a Girl Like You”

The aspiring pool cleaner whipped out his acoustic guitar to soothe baby Beth to sleep. But his sweet crooning of this ’80s slow dance classic from Foreigner seemed to charm mother Shelby as much as the child. A cheesy moment? Yes. But given the baby’s presence, sort of sweet. And Mark Salling did a nice job of playing the Lou Gramm role. Grade: B.

The Troubletones, led by Mercedes, Britney and Santana: “Candyman”

In order to demonstrate what a genuine threat the new show choir in town presents, the girls Christina Aguilera’d it up very effectively. Side note: As part of her anti-arts crusade, Sue Sylvester (Jane Lynch) complained that McKinley’s production budget for “West Side Story” was $2,004. Seriously? I’m pretty sure the production budget for this rehearsal performance of “Candyman” — with all those perfectly tailored Andrews Sisters-style costumes — cost at least that, if not more. Grade: A-

Rory: “Take Care of Yourself”

This was McGinty’s break-out moment. After being recruited by Finn to join the New Directions, he performed this lovely version of Teddy Thompson’s “Take Care of Yourself,” in a way that ensured that much Gleek swooning — or in Kurt’s case, jealous eye-rolling — would ensue. A song by a British artist for an Irishman may be an unconventional choice. But the “Glee Project” champ handled it with adorable aplomb — so adorable, in fact, that Darren Criss might want to watch his back. Grade: A.

What did you think of this week’s numbers and this week’s episode of “Glee”? And more importantly, how do you feel about the addition of Rory “Non-Fighting Irishman” Flanagan? Weigh in by posting a comment.