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.

I loved those scenes,” Lizzy Caplan told DECIDER. “We knew from very early on that there was a rich history that we wanted to convey.” That history includes Alex’s deceased brother, Nick (Jackson Eick).