Over a persistent ticking sound, Jon introduces himself: “The sound you are hearing is not a technical problem. It is not a musical cue. It is not a joke. It is the sound of one man's mounting anxiety. I... am that man.” Jon is an aspiring composer for musical theatre, who lives in SoHo, New York. He is nearing his 30th birthday and worries about his aging and lack of achievement (“30/90”). Michael, a friend of Jon’s since childhood, gave up acting to pursue a more lucrative career as a research executive. Susan, Jon's girlfriend, is a dancer who teaches ballet to “wealthy and untalented children.”
Susan and Jon discuss the upcoming 30th birthday party that she is throwing for him. She pressures him to play “Happy Birthday to You” to himself on the piano at the party, but he is hesitant because it reminds him of the aging aspect of birthdays. Michael wants to schedule a job interview for Jon with Michael’s firm. Again, Jon is hesitant, but agrees to think it over. Later, on the roof of his apartment building, Jon reveals that he is also nervous about an upcoming workshop of his newest musical, SUPERBIA. Susan comes to join him; he comments on her dress and how beautiful it makes her look (“Green Green Dress”).
The next morning, Jon is awake early. Susan asks him about the possibility of leaving New York. Susan wants to raise a family and doesn’t view that as compatible with Jon’s “starving artist” lifestyle. Jon is torn between following his dream of composing and opting for security and family in a different career. Meanwhile, the other two main characters recap their views on what Jon should do (“Johnny Can’t Decide”). Jon’s reverie, however, is cut short; he needs to report to his day job as a waiter in a SoHo diner (“Sunday”).
After work, Michael picks Jon up in his brand new BMW to show Jon his new apartment. Michael exults at the thought of a life of luxury (“No More”), and pressures Jon further to consider changing his career path. Frustrated, Jon finally agrees to accompany Michael to work the next day and visit a brainstorming session at his firm. Back at home, Jon phones his parents and then his agent. He plans to spend the remainder of the evening composing, but he is interrupted by a call from Susan, who wants to see him. They argue, albeit in a passive and psychological manner that scarcely seems like an argument at all (“Therapy”).
On Monday morning, Jon walks to Michael’s office for his brainstorming session. On the way, Jon thinks back to a workshop in which his work was reviewed by a composer “so legendary his name may not be uttered aloud…” (“St----- S-------”). He also worries about his musical style and its place on Broadway, but has little time to develop this train of thought before he arrives at Michael’s firm. The brainstorming session involves naming a cooking fat substitute through a convoluted “idea-generating” process. Jon sees the futility of the process, and his unwillingness to cooperate gets him removed from the meeting. Later, as Jon drives Michael to the airport for a business trip, they argue about the meeting. Michael tells Jon that the life Susan wants doesn’t sound bad, and that he wishes his job could give him the chance to settle down (“Real Life”).
After dropping Michael off, Jon goes to a rehearsal for SUPERBIA, but not before stopping to get a snack of Twinkies (“Sugar”). At the market, he spies Karessa Johnson, one of his actors for SUPERBIA. She reveals a similar weakness for Twinkies, and this leads to a sudden friendship between the two. After the rehearsal, Susan sees Jon and Karessa walking together and becomes jealous. She informs Jon that she’s gotten a job in Northampton, Massachusetts which may be permanent. Jon and Susan argue about the state of their relationship; in a turnaround from the events leading up to “Therapy,” Jon begs Susan to stay and be with him. Despite this, she leaves for home, and Jon thinks about what may have happened to make her behave this way (“See Her Smile”).
The next morning, Jon arrives early at the theatre for the workshop of SUPERBIA. Although initially the theatre is empty, soon it is filled with very important people: Jon’s family and friends, as well as Broadway producers and artists, including Jon’s idol, St----- S-------. Karessa steals the show with her performance of “Come to Your Senses”. The workshop is a success, and Jon gets many congratulations; but there are no offers to produce SUPERBIA on or off Broadway. Jon is no closer to being a professional composer, and so, in his eyes, the workshop has been a failure.
After the workshop, Jon visits Michael and tells him that he is through with music. For the first time, though, Michael tries to persuade him to stick with it. Michael says that while he enjoys how he makes a lot more money now than he did as a starving artist, he finds the job itself to be emotionally banal and unrewarding. The two argue, and Jon yells at Michael for not understanding fear or insecurity. Michael responds by telling Jon that he is HIV-positive. Shocked at this news, Jon leaves quickly.
Distressed and alone, Jon wanders through Central Park until he finds himself in the abandoned theater inside Belvedere Castle. He finds an old rehearsal piano, and begins to play it while collecting his thoughts. Jon ponders on whether the amount of sacrifice required for his career in music is worth it, and whether those telling him to “have it all, play the game” are right (“Why”). Ultimately, he realizes that he will only be happy as a professional composer, no matter what hardships that may bring.
The next morning is Jon’s thirtieth birthday party (“30/90 Reprise”). He sees Susan, who is getting ready to leave. She gives him his birthday gift: a thousand sheets of blank manuscript paper. They agree to write to each other, and she leaves. Michael gives him a birthday gift of belts (Michael thinks belts are a sign of luxury). The phone rings, and the caller is Stephen Sondheim. Sondheim leaves Jon his contact information so they can meet and discuss SUPERBIA. Jon realizes that he is surrounded by friends and that his talents are finally being recognized. He says, “the tick tick booms are softer now. I can barely hear them, and I think if I play loud enough I can drown them out completely.” Jon sits down at his piano to play “Happy Birthday to You.”