Club member Sam (Chord Overstreet) creates a tribute band to teen singer Justin Bieber in order to win the heart of Quinn (Dianna Agron), and is later joined by the group's other male members, minus co-captain Finn (Cory Monteith), to recreate Bieber's "Somebody to Love" and woo their significant others.

Prior to broadcast, Murphy dismissed rumors that "Comeback" would serve as a tribute to Bieber, and stated that such episodes are reserved for artists with extensive musical catalogs.

After her cheerleading squad loses a competition for the first time in seven years, coach Sue Sylvester (Jane Lynch) becomes depressed, and stages an apparent suicide by "overdosing" on gummy vitamins.

Hoping to create discord within the group, Sue pits members Mercedes (Amber Riley) and Rachel (Lea Michele) against one another.

In an attempt to bring out the good in Sue, club director Will Schuester (Matthew Morrison) takes her to a pediatric cancer ward, where they sing "This Little Light of Mine" with the patients.

Several of the male members—Puck (Mark Salling), Artie (Kevin McHale) and Mike (Harry Shum Jr.)—are impressed by the effect he has on the girls, and convince him to let them join his tribute band.

Series creator Ryan Murphy refuted the claims, and stated that such episodes are reserved for artists with extensive musical catalogs.

He confirmed, however, that Bieber's music would be used in an episode in season two as a "small plot point", and Overstreet's Sam would perform a song by the artist for Quinn's approval.

[2] On the red carpet at the 68th Golden Globe Awards, cast member Riley confirmed to MTV News that Bieber's songs "Baby" and "Somebody to Love" would be featured in the upcoming episode, and the singer would receive a tribute similar to Lady Gaga in "Theatricality"—a tribute, but without a full episode devoted to his catalog.

[5] The pediatric oncology scenes were filmed at the Children's Hospital Los Angeles' Center for Cancer and Blood Diseases, where eleven real patients performed alongside Morrison and Lynch.

[6] Bailey, the pediatric ward nurse, was played by guest-star Charlene Amoia, who had worked for the series' sound department during the first season.

In June 2011, she deemed her "Comeback" appearance her favorite guest role in any series, due to working alongside the children, whom she was "so touched by".

[7] The episode's recurring guest cast members were Overstreet as Sam, Iqbal Theba as Principal Figgins, Shum Jr. as Mike and Fink as Lauren.

[20] CNN's Lisa Respers France found the episode's title apt, as Glee was "firing on all cylinders" with little room for improvement.

Club's Emily VanDerWerff felt that "something was missing, making the whole thing stultifying, lifeless, and boring",[25] and Robert Canning of IGN deemed it "fine and inoffensive", but ultimately forgettable.

[27] While VanDerWerff was more favorable, he wrote that Sue's jokes about committing "Sue-icide" were "neither dark enough to provoke a startled burst or laughter nor funny enough to overcome their central tastelessness", and called the scene in the pediatric oncology ward "woefully misjudged and inappropriately hilarious".

[25] The Atlantic's Meghan Brown found the use of seriously ill children "borderline offensive", and called Sue's suicide attempt "in totally bad taste".

He praised Glee for capturing the "disposable fun" of Bieber's music, "without either sneering at it or making it more than it is", and called it better in this respect than "The Power of Madonna".

While VanDerWerff found her relationship with Puck "a lot less assured" than in "Silly Love Songs",[25] Mullins and Gonzalez praised their "endearing" dynamic.

[19][24] Reiter felt that in "Comeback", while new characters like Sam and Lauren "managed to shine", established favorites fared less well: "Finn continues to be dismayingly drained of all that once made him so adorable, and Rachel, too, has been deprived of the depth and sex appeal she so carefully developed over time.

Hankinson wrote that the songs "blended all of the show's best charms", which he listed as "kitschy suprise [sic]", "slick production" and "raw vocal ability".

Although she complimented the male vocalists and their "almost perfect re-creation" of the video, Gonzalez was disappointed the show chose to repeat, rather than reinterpret, the choreography.

[23] Raymund Flandez of The Wall Street Journal expressed disappointment in the Bieber performances "displayed so awkwardly and so undynamically" by Sam.

Countering with her unique brand of runs and range, Riley sassed up the arrangement with enough melisma to make the Glee version of the oft-covered modern musical theatre staple its own aural utopia.