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.

Karen finds herself seduced by the glamorous life of new BFF Rebecca Duvall -- but can Rebecca be trusted? What will Karen's ascent mean to her relationship with Dev? And will Rebecca drive Derek insane? Eileen introduces new beau Nick to ex-husband Jerry, while Julia panics when her son Leo goes missing.

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.