'Glee' Season 5 Episode 10 Spoilers: Rachel and Santana's Feud Reaches a Boiling Point [Video]

"Glee" returned from a lengthy hiatus with an episode about what happens when your friend suddenly becomes your greatest rival.

In "Frenemies," Tina (Jenna Ushkowitz) and Artie (Kevin McHale) find out that they're tied for valedictorian. Tina wants Artie to withdraw so she can get off the waitlist and get into Brown, and Artie calls Tina the "meanest person at school this year."

The duo also competes for the one remaining solo at Nationals with En Vogue's "My Lovin' (You're Never Gonna Get It)". They then try to win over a panel of judges deciding their Valedictorian status by trying to elicit sympathy.

Their transparent plan backfires, and Sue (Jane Lynch) bumps them both to salutatorian and gives the spot to Blaine (Darren Criss).

Blaine agrees to sing with Artie and Tina at graduation instead of giving a speech.

In New York, more characters fight for the spotlight. Kurt (Chris Colfer) accuses Elliot (Adam Lambert) of trying to steal his thunder, but later begs him to teach him guitar. They go into a guitar store, where they do a duet of The Darkness' awesome rock song "I Believe in a Thing Called Love." They eventually patch things up, and even take selfies together.

Meanwhile, Santana (Naya Rivera) is getting down on herself for lagging behind her other friends in achieving her dreams. She accompanies Rachel (Lea Michele) to her New York Magazine photo shoot, where she fantasizes about sharing the spotlight as she and Rachel do a duet to Sara Bareillies' "Brave."

Later, Rachel freaks out when she hears they are casting her understudy. Santana comes to audition for the understudy, and sings "Don't Rain On My Parade" as her audition number.

Santana's unique take on the song, as well as the history between her and Rachel, convinces the director to cast Santana as Rachel's understudy.

Once they're back home, Rachel yells at Santana, and later demands that Santana move out. Santana refuses, so Rachel packs her bags and leaves, ripping up a graduation picture of her and Santana as she leaves the loft.

In future episodes, other characters will also have complicated relationships.

In upcoming Episode 13, Blaine will graduate high school and join Kurt in New York, but that doesn't mean the two will live happily ever after.

"You have them engaged and together, and it's a different world," executive producer Brad Falchuk told TVLine. "It can be both harder and easier to see a person every day."

But first, in the next episode, titled "Trio," Will and Emma will focus on making a baby.

"We're trying to conceive a child," returning guest star Jayma Mays confirmed. "There's something wonderful about those two people creating a family, and continuing their life together and the journey that they are on.

"We're going to make a Wemm-fant," the actress added.

Watch a sneak peak of Will and Emma in the next episode here.

TVLine also released exclusive photos from tonight's episode, including Dani (Demi Lovato) donning a tux and performing with the Pamela Lansbury's, as well as Emma and Will cuddling up.

There are also photos from the March 11 episode "City of Angels," in which the New Directions go west for Nationals, where they'll reunite with Mercedes (Amber Riley), Burt (Mike O'Malley) and Carol (Romy Rosemont).

Check out the photos here.

The synopsis for the upcoming episode reads: "Graduating seniors Blaine, Tina and Sam get more than they bargained for when they try to create an epic, lasting memory of McKinley High. In NYC, the continuing diva battle between Rachel and Santana hits a tipping point, leading to big changes for them and their circle of friends. Will and Emma are anxious about being unable to conceive a child."

EP Falchuk also hinted at a possible love connection between Rachel and Sam (Chord Overstreet) once Sam comes to New York.

Then on the 100th episode, Jane Lynch teased that Sue will reluctantly disband the New Directions, but some blonde megastars will try to save the day.

"The kids and Gwyneth Paltrow's [Holly Holliday] and Kristin Chenoweth's [April Rhodes] hatch plans to get the glee club back in the auditorium and up and running," Lynch said.

Watch the promo for the next episode below, which airs Tuesday, March 4 at 8 p.m. EST on Fox.