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.

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.

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.

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.