As Black Lightning (Cress Williams) departs on a special mission, he does so with the full support of Gambi (James Remar) in the new episode "The Book of Ruin: Chapter One." Elsewhere, Grace (Chantal Thuy) tries to persuade Anissa (Nafessa Williams) to let her guard down a little. China Anne McClain, Christine Adams, Marvin Jones III and Jordan Calloway also star.