The episode begins, and Julia is frantically switching scenes around as Tom and Derek watch. Derek is more than a little annoyed with her, and rightfully so; the workshop performance is getting closer every day, but Marilyn's book and lyrics still aren't close to being finished. It seems that adultery is acting as a dam for Julia's creative flow. Karen, meanwhile, is busy gasping, first over the ever-changing script and then over her astronomical credit card bill. Dancer Sue doesn't see what the big deal is, since she only owes $326.38: if her own bill were that low, she'd be "singing and dancing," says Sue. "You'd be singing and dancing anyway!" Bobby and Jessica reply in unison. See, they simply cannot do it alone!
Ellis scurries over to Eileen's office and tells her that Marilyn is basically in shambles. She grabs her stuff and heads to rehearsal just in time to see Ivy totally choking while singing "Let Me Be Your Star." Her once-perfect voice is suddenly sounding pretty pitchy; she can't even get close to hitting the notes she usually nails easily. If Ivy suffers the same fate as poor Julie Andrews, I might burst into sobs. Ivy and Tom head to the doctor while the rest of the cast continues rehearsing. Shortly after Derek dismisses everyone, Tom returns and tells the team that Ivy's throat is inflamed. Though the doc has prescribed a steroid, Ivy is hypersensitive to drugs and doesn't want to take it.
Everyone else, though, is concerned that mere vocal rest and tea won't be enough. Derek doesn't waste time suggesting that they ask Karen to fill in for Ivy. Tom's completely against the idea -- if Ivy finds out, it'll only freak her out more. As they discuss their options, they have no idea that Karen is still in the room. That evening at Ivy's apartment, Derek nonchalantly urges his leading lady to take the Prednisone she's been given. He calls the drug a miracle worker. Ivy's worried about side effects, but as Derek says, she works in musical theater. And, on a more serious note, if she doesn't get well they'll have no choice but to ask Karen to fill in. That's all Ivy needs to hear. She reaches into her Marc by Marc bag and pulls out her magic pills. Julia's going through some tumult of her own.
At rehearsal, Michael keeps trying to get her to see him alone, and she keeps shooting him down. Even so, she can't help daydreaming about their passionate smooch as she makes pancakes for her son. Her reverie is so intense that it causes her to burn breakfast, giving Leo yet another reason to hate his mom. He's clearly livid about what he's seen. Things don't really get less tense when Husband Frank suddenly returns from Far Far Away, totally oblivious to what's happened in his absence. At rehearsal, a visibly distraught Ivy tells Derek that the Prednisone is giving her cold sweats, a headache, anxiety, a gash, a rash, and purple bumps. All the director cares about is whether her voice has healed. And because Ivy isn't already feeling bad enough, he reminds her once more that Karen's going to step in if she can't sing. Ellis pops by Eileen's office unannounced to let her know that Ivy's voice is sounding great. Instead of shooing him away, Eileen accepts Ellis's info.
When he asks if she needs anything else, she considers him carefully. We next see Ellis and Eileen walking through a gorgeous high rise apartment. Ellis's buddy Zach apparently works for its broker; the space isn't even on the market yet, but he's pulled some strings to show it to Eileen. After leaving the apartment, the bright young things take Eileen to a bar called The Bushwack. Terrible is really working hard to get the producer on his side. They drink $7 martinis and manage to play Big Buck Hunter without feeding the game any quarters. Suddenly, Eileen starts to feel like she's 24 instead of as old as time. Tom plays a melody for his partner, but tortured-looking Julia is still way too distracted to pay attention to anyone but herself. Finally, she confesses that Michael kissed her.
Tom, to his credit, manages to sound pretty non-judgmental while telling her that she has to think about her family. Not to mention Michael's family. Ivy stares at her reflection in her mirror, then sings, "I stare at my reflection in the mirror." Like Karen before her, Ivy is belting alone in her bedroom; this time, the tune is "Who You Are" by Jessie J. Her voice sounds great. After proving that her instrument is as finely tuned as ever, Ivy stops singing. "It's fine! It's going to be fine," she says to herself. But the vision of Karen-as-Marilyn that suddenly appears in Ivy's mirror thinks differently. Yup: Ivy is hallucinating. Because of arthritis medication. Karen is filling in for fellow ensemble member Jessica at a bar mitzvah. Ivy's apparition freaks her out so much that she texts both Sam and Tom, asking if they can come over.
They arrive and instantly start trying to calm down the blonde, who's worrying about bloating and growing wolf-like hair. Prednisone is a hell of a drug. Tom, at least, doesn't mind ditching his plans to come to Ivy's aid -- her call came when he was in the middle of an unbelievably dull cocktail party at John Lawyer's place. Julia's world almost comes crashing down when Michael calls her at home, yet again -- and Frank answers the phone. She manages to wrench the receiver away and takes it outside, where she hisses that Michael seriously, seriously has to stop. DiMaggio, though, won't take no for an answer. He asks her to meet him in the rehearsal space at 10pm, then leaves to deal with his poor unsuspecting wife and son.
Though Julia has no intention of meeting Michael, eventually her resolve weakens and she heads back to Manhattan. Tom sends word to Karen, saying that she might need to step in as Marilyn. The news invigorates Iowa enough to sing a spirited rendition of Hava Nagila, even though she doesn't know the words. She follows it with a pretty take on Florence and the Machine's "Shake It Out." As Karen does her best Flo impression, legions of bored kids are drawn to the dance floor, where they groove as only awkward 13-year-olds can groove. Julia arrives at the rehearsal space, determined to shut Michael down once and for all. But one thing leads to another, and soon enough he's unbuttoning her sultry PJ top. The meeting ends as we all guessed it would: with the lyricist and DiMaggio going at it on the rehearsal room's couch.
The next morning at rehearsal, Derek breezily asks Ivy how "the voice" is. Ivy edgily replies that "the voice" is fine: "Do you want to know how I am?" The answer, of course, is no. When Karen arrives, Tom apologizes for sending her confusing texts; it turns out, of course, that Ivy doesn't need a stand-in. Though today won't be her big Marilyn break, it could very well still be a milestone: a music exec named Bobby Raskin heard her sing at the bar mitzvah, and he wants Karen to give him a ring. The gang gets down to business, and we see them perform a stripped down version -- no dream stage tonight -- of "History Is Made at Night." It appears that Julia's late-night rendezvous with Michael inspired her to finally finish the song's lyrics. As the stars are reaching the song's climax, Ivy accidentally loses her footing on said sex couch and collapses into giggles.
Derek, though, isn't laughing. He makes a snide comment about Ivy not being sexy enough, thus provoking Ivy to deliver a venomous, drug-influenced rant. As the rest of Marilyn's team watches, fascinated and horrified, she screams at Derek for humiliating her once more and suggests shrilly that maybe they should just ask Karen to step in. She finishes by calling the director a narcissistic prick who isn't that good-looking -- or that good in bed -- before storming out into the hallway. Eileen isn't around to witness this latest bit of drama. She's happily ensconced at The Bushwack with Ellis and Zach -- and this time, she's asked a potential investor to join her at the dive as well. The episode ends with an iconic shot of Eileen picking up the plastic Big Buck Hunter gun and gleefully taking a shot.