While Will is trying to back off his excessive spending habits, Fiona is in search of an emergency contact for Marcus. Although she asks Will, she's not sure he's quite up to snuff. Marcus isn't bothered either way, because he's drunk with power, ready for his first day as Princi-Pal, acting as the school principal's protégé. Will protests: this will ruin Marcus' social rep once and for all! Fiona just thinks this is an example of Will's innate inability to embrace responsibility.
Marcus and Principal Goldenrod are a match made in heaven, until Shea Garcia-Miller sneaks into the principal's office to take over the PA system, blasting the Sex Pistols throughout the school. Marcus is immediately smitten, and when Principal Goldenrod walks in to find Shea dancing on his desk, Marcus takes credit for her revolution. After school, Marcus tells Will he's a little proud, until he realizes Marcus is suffering from his first big-time crush. Quickly recognizing Shea as a bad girl, Will invokes the bro-code of silence; he won't tell Fiona about Shea, but Marcus should tread carefully.
The next day, Marcus is sitting outside Principal Goldenrod's office waiting for Fiona when Shea sits down next to him. After she refutes many school rumors - she has never eaten a live squirrel - Marcus is even more smitten, which is immediately apparent to Fiona. Principal Goldenrod tells Fiona he's devastated; he's never felt more betrayed by a student. Fiona urges Marcus to tell the truth about the Sex Pistols incident, but with a glance at Shea, he fervently redeclares his guilt. Fiona stomps over to Will's to explain she's banning Marcus from speaking to Shea. Bolting out of the dumbwaiter, Marcus pleads for Will's help - he has to see Shea! Will is just asking for evidence that Shea actually likes Marcus when the doorbell rings. Marcus ducks behind a chair, but Shea spies him right away. Will does his best to kick Shea out of his apartment, but when she questions his cool factor, Will rallies - it's on. Will goes the distance to prove how awesome he is and an afternoon of video games, football, smoothie-chugging and music-making ensues. When Will performs a shrill guitar solo, Fiona comes barging in and the jig is up. She's driving Shea home.
Hoping to speak with Shea's parents, Fiona is chastened to see the messy apartment where Shea sleeps on the couch usually alone, and her intended dinner of cookies and cigarettes. Back at Will's, Marcus is all nerves - what's taking his mother so long? Fiona just doesn't get what being in love is like. Upon her return, Fiona admits Shea's not a bad kid. But she is a year older than Marcus and in a very different place. Fiona still doesn't want Marcus hanging out with Shea, and hopes he'll understand. When Marcus appeals to Will, he apologizes. What Fiona says stands. Later, Will explains to Fiona that he doesn't take being Marcus' emergency contact lightly. For her part, Fiona doesn't take parenting lightly. Rather than being black and white, it's quite gray. Will offers up an aged whiskey as the answer, but when he goes to look for it, he realizes Shea is the only person how could possibly have taken it. Meanwhile, Marcus struggles to write a letter of apology to Principal Goldenrod. He tries to ignore a text from Shea... but her rock 'n' roll spirit wins him over yet again - letter of apology aborted!