In the pilot of Smash we are introduced to Tom Levitt and Julia Houstona song-writing duo who had planned on taking a break from the business of Broadway but, find themselves drawn back in when they get the desire to produce a musical based around the life of Marilyn Monroe. When a demo of one of the tracks goes viral the project attracts the eye and ear of tenacious producer Eileen Rand and, although causing a conflict that of director Derek Wills. But the biggest and most important task is to find their Marilyn after, auditioning a range of girls they whittle it down to two but, who do they go for. Ivy Lynn a veteran of the stage who wants to break away from the chorus line to get her break as a lead or Karen Cartwright a fresh talent who is trying to follow her dream of becoming a star.

Ivy and Karen jump through hoops for the brilliant but temperamental director Derek Wills as they pursue the role of a lifetime. Meanwhile, Julia and her husband Frank, are frustrated by the red tape of an international adoption process, and Eileen fights to finance her new musical in the midst of an acrimonious divorce.

The search begins for a Joe DiMaggio to play opposite Marilyn - but everyone's first choice, Michael, has a secret. Karen returns to Iowa for a baby shower and must decide what she wants for her future. Eileen begins rounding up investors - but ex-husband Jerry may already have poisoned the well.

Karen must learn to advance in the high-stakes world of Broadway, as Derek hosts a party for hot young star Lyle. Eileen tries a sly new strategy for raising funds, while Tom goes on a first date.

Karen finds a new use for her acting talents as she joins Dev at a high-powered government party. The drama between Michael and Julia heats up, as Eileen and Tom's ambitious assistant Ellis forge an alliance. Ivy senses trouble in her relationship with Derek.

Ivy faces major vocal issues, while Julia struggles to avoid Michael. Meanwhile, Karen books a side gig at a bar mitzvah.

Eileen, Derek and the team present ''Marilyn the Musical'' to would-be investors. Ivy struggles to perform. Karen must make a difficult choice. Julia and Michael face the consequences of their actions.

The team deals with the workshop's after-effects; Derek asks Karen to help him steal the show from Tom and Julia; Eileen's daughter's surprise visit forces her to deal with her ex-husband.

Julia and Tom must find a title for the recently reinvigorated musical; Ivy and Karen compete for an orange juice commercial; Frank makes a discovery.

When the show's new star gets stuck in Cuba, Derek puts Karen in as understudy; Tom and Julia celebrate their anniversary.

The arrival of a movie star turns ``Bombshell'' upside-down; Ivy and Karen try to overcome their history and unite against their new rival; Tom and Sam's romance heats up.

Ivy worries as Derek grows closer to Rebecca and Karen has to choose between Dev and the show. Ellen and Julia fight over Michael's possible return and Sam brings Tom to a family dinner.

"Bombshell" faces its first audience just as a major crisis hits Rebecca Duvall. The team of Tom and Julia scramble to fix the show when the first preview falls short, and Frank must adjust to the unwelcome return of Michael Swift to his life. Dev seeks reconciliation with Karen, but explosive information about Ivy lurks just beneath the surface.

Tom and Julia work to save the show, while Derek makes a decision that will forever change Karen's and Ivy's lives; Ellis tries to save the show.