Jessica Biel’s latest series, “Candy,” is based on the true story of Candace Montgomery — a do-it-all mom who snaps after years of repressing her anger and kills her lover’s wife with an ax. “I understand her rage,” says Biel, relating to the stresses of projecting a perfect image in public. In this episode, she discusses why she’s drawn to playing antiheroes, how scrutiny of celebrities has changed since she was starring in “7th Heaven,” and the heated debates that she and husband Justin Timberlake — who makes a cameo in “Candy” — had about the murder mystery.