This interview contains spoilers from all six episodes of "Zero Day," now streaming on Netflix. Lizzy Caplan always knew that her character, Congresswoman and former First Daughter Alexandra Mullen, was behind the catastrophic cyberattack that incited the existential and moral panic that runs through "Zero Day.

As former U.S. president turned special commission investigator George Mullen ( Robert De Niro) delivers a climactic closing speech in the final scene of Netflix's new political thriller Zero Day, it's this admission that gets to the heart of the show's message about the importance of truth in today's world.

The Oscar-winner embraces US TV for the first time in a new limited series that prioritizes conversation over action, but is still compelling.