In 1950s Hollywood, aspiring young actress Marla Mabrey (Lily Collins) and her ambitious young driver Frank Forbes (Alden Ehrenreich) struggle with the absurd eccentricities of wildly unpredictable billionaire Howard Hughes (Warren Beatty), whom they work for.
Marla is a strict Baptist who cannot fraternize with boys, much to the chagrin of Frank who, despite his mounting attraction, is forbidden to make a move for fear of losing his job. However, the two eventually come to the conclusion that the rules "don't apply" to them. Their situation is made even more tense when Hughes begins making passes at Marla. And things really start to heat up when Hughes puts a ring on Marla's finger.