On Glee Season 6 Episode 8, Brittany's mom takes the engaged couple to the barn where Brittany was born to tell them she thinks they should get married there. Artie and Ms. Lopez agree that it's totally do-able and their friends set out to make the barn perfect. Brittany begins to panic about all the last-minute details they still haven't worked out. Kurt decides Burt should officiate the wedding.
Santana and Brittany take turns having a fashion show at the bridal shop showing off their gown ideas. Santana walks out of the dressing room and sees Brittany in her dress and Brittany's freakout begins again. Later she decides she and Santana need to slaughter a chicken to ward off the bad luck. Santana talks her down and Brittany sets a chicken loose in the halls of McKinley.
Rachel doesn't want to sit with Sam at the wedding because she's afraid it will upset Carol and Burt. Mercedes and the others remind her that they both lost someone too and Rachel agrees to be seated with Sam. Santana sees a seating card with Sue's name on it and doesn't understand why she's invited. The others point out that if they don't invite her there's a 99% chance she'll ruin the wedding. Santana vetoes inviting Sue.
Kurt tells Walter he's going to the wedding with Blaine. Walter says he understands and tells Kurt he's lucky and not to give up on love. Kurt runs to Blaine's apartment, where Blaine is busy moving out, and declares his love and asks Blaine to go to the wedding with him.
Tina assembles Puck, Blaine, and Artie and says she wants to ask Mike to marry her. Artie and Puck tell her she's crazy while Blaine says he thinks it's romantic. She and Mike have been texting and she believes Mike is her best friend. Puck and Blaine give her the go-ahead and Artie does as well, though reluctantly.
Santana visits Sue at Sue's behest. Sue says she's hurt that Santana doesn't want her at the wedding. Santana calls Sue selfish and warns her not to show up lest she be forcibly removed. Sue looks visibly upset.
Prior to the wedding, Carole and Blaine's mom meet for the first time. Friends and family mill about taking pictures. Burt and Carole talk to Kurt and Blaine about seizing the day and enjoying everything life has to offer. Behind the scenes, Brittany continues freaking out, sending Mercedes, Tina, and Rachel out to find good luck charms to ward off the bad luck she's certain is plaguing her. Santana enters the room and tells Brittany that the bad luck she's buying into isn't real.
Sue walks into their dressing room and brings Santana's abuela with her as a wedding present. Sue managed to talk Abuela into showing up to the wedding to support Santana and Brittany even if she doesn't agree with their marriage. While they have a moment, Sue runs a special errand for Brittany.
She returns with Kurt and Blaine and Brittany reveals her plan to make this a double wedding. Sue, Brittany, and Santana have thought of everything from the tuxes to the rings. All the guys have to do is say yes.
Mercedes and Artie sing "At Last" as Kurt escorts Brittany down the aisle in a black tux. Blaine enters with Santana on his arm. The different tuxes send off alarm bells in the audience. Burt begins the double ceremony and the two couples recite their vows to one another.
Brittany's father gives the most awkward wedding speech imaginable before the New Directions, old and new, and wedding guests break into "Hey Ya" to start the reception. Mike tells Tina to make sure she doesn't leave before they get the chance to dance and Tina decides to propose to him. Mike says he can't marry her. He loves her, but now is not the time for that discussion.
Gloria Estefan, playing Santana's mom, sings with the Treble Tones, Blaine's mom, Carole, and Brittany's mom. The newlyweds invite all the couples to the floor and perform "Our Day Will Come."
After the wedding, Artie recreates their Tuesday lunch to discuss Tina's failed attempt at getting engaged. They decide to be each other's back-up plan. If they're not married to anyone else when they turn 30, they'll marry each other.
Sue has one last gift for the newlyweds. But it's not a song.