We begin in a dive bar in Brooklyn, as the band Ironic Maiden (led by hipster alpha-male Jake) finish the final song of their set ("Brooklyn Crush").
As the band puts their gear away, frontman Jake’s nerdy best frenemy (perpetually single children’s puppeteer Christian Schwartzelberg) chats with the stoner bass player’s longtime girlfriend (Ivy). Ivy gives Christian some titillating info: her beautiful singer-songwriter friend (Juliana) has just moved to Brooklyn and is on her way to the club. The news re-ignites Christian and Jake’s lifelong romantic rivalry ("Why?”). But eventually Christian convinces Jake to leave the club so he'll have a shot with Juliana. Juliana arrives and Christian is instantly smitten ("Juliana"). After he gets up the nerve to ask her out, Juliana admits that she is still recovering from her last relationship and doesn’t want to jump into anything prematurely, but she agrees to hang out with Christian again.
On a “non-date” the next day in the park, Juliana confesses to Christian that she gets debilitating stage fright when performing her music. Christian tells Juliana about an open mic the next night and promises to be there to support her. Then he convinces her to improvise a song with him in the park ("Something I Just Like About You") as a way to get over her fear of performing in public. Juliana and Christian get swept up in the fun of singing together and at the end of the song Juliana spontaneously kisses Christian. But the moment is ruined when Jake shows up and can’t help himself from sabotaging his best friend’s romantic hopes. As Christian looks on distraught, Jake flirts with Juliana and invites her to his band’s next show.
Meanwhile, Tony (the weed-loving bass player in Ironic Maiden) relaxes at home and sings an ode to his bong ("Me and My Bong"). Ivy comes home and argues with “Stony Tony” about how dysfunctional their relationship has become ("Sticking Around").
Later that night, back in the club, Jake and Ironic Maiden close their set with a song about the frontman’s sexual prowess ("Please You"). After the show, Jake flirts again with Juliana and takes the aspiring musician on a private tour of the club. Left alone, Ivy confesses her true feelings about her “bestie” Jake ("If You Were Mine"). Backstage, a confused Juliana struggles to reconcile the physical attraction she feels for Jake with her affection for the much sweeter (but dorkier) Christian ("Hot"). Ultimately, Juliana gets caught up in the moment and Christian shows up just in time to see Jake and Juliana kissing. Juliana instantly regrets making out with Jake and rushes to find Christian but he’s already gone.
The next morning, back in the park, Christian (whose kids shows use puppets designed to look like his favorite celebrities and who sometimes “bounces ideas off them”) is getting conflicting advice from his aggressive Iggy Pop puppet and his sulking Robert Smith puppet when Jake shows up to call a truce. In order to succeed with Juliana, Christian decides that he's going to have to be more of an alpha-male like Jake and asks his buddy to help him transform ("Be My Bro").
That night, in a bar in a grittier part of town, Arielle, a booking agent at one of Brooklyn’s hottest rock clubs, brags about her globe-trotting adventures ("Fuck-it List"). When the boys see her, Jake cowers in her presence (since he’s dying to book a gig at her venue) and Christian tries too hard to act cool. Arielle is charmed by this and invites them both to her place for the next adventure on her list: a ménage à trois. Meanwhile, Juliana gets up the nerve to play at the open mic and sings a song she wrote for Christian ("Falling"), even though he isn't there to support her.
In Arielle's apartment, she and the boys begin to get to know each other more intimately ("Arielle's Areolas"), but Jake has an embarrassing accident and has to leave before the main event (although he does manage to score a gig for Ironic Maiden at Arielle’s venue out of pity). After Jake’s “premature” departure, Christian breaks down in front of Arielle, certain he'll always be a loser. Arielle convinces Christian he deserves better treatment than what he's been receiving from Juliana. And Christian leaves her apartment determined to never let himself be walked on again. Meanwhile, Jake runs into Ivy in the park and discovers he's attracted to her and they both try not to express their feelings ("Awkward Silence").
Heading home, Christian finds Juliana waiting on his stoop. She apologizes for kissing Jake but, trying to follow Arielle’s advice, Christian is cold and cruel to Juliana. After she storms off, Christian realizes he's made a huge mistake (“Brooklyn Crush (Reprise)”).
The next day, Tony discovers he has feelings for someone who is helping him know himself better ("Getting High"). Meanwhile, Christian hatches a plan to win back Juliana. Via email he convinces Arielle to let Juliana play instead of Ironic Maiden and gets Jake to agree to the plan ("Email Song"). Christian finds Juliana in the park and convinces her to give him one more chance ("Take Me As I Am") and gets her to agree to come to Arielle’s club that night for a surprise.
At the club, Tony and the drummer give in to their growing feelings for each other and kiss. Jake and Ivy enter just in time to see this and Ivy is relieved because it frees her to be with Jake. Christian enters just in time to see both new couples making out. Juliana enters and Christian tells her she's playing tonight. The band, who have learned Juliana’s songs, back her up and she and Christian reunite ("Falling [Reprise]") and the three new couples (and one potential triad) reap the rewards of being themselves ("Take Me As I Am [Reprise]").