When a violent shooting rocks a Los Angeles nightclub, Hondo and 20-Squad are thrust into the dark world of sex trafficking, going head-to-head with a notorious biker club as they race to find a missing girl. Meanwhile, a figure from Alfaro's past resurfaces, raising the question of whether his wounds run too deep for forgiveness, and deputy chief Bennett pushes commander Hicks to the breaking point.

When Hondo's ne'er-do-well cousin, Andre, goes AWOL from his Marine base during basic training, Hondo, Deacon and Daniel Sr. take a road trip to get the kid in line. But when they learn that Andre witnessed an illegal arms deal involving stolen military weapons, Hondo realizes there's a darker explanation for Andre's disappearance. And Alfaro plots to work outside the law when he discovers that his mother's long-ago abusive ex is back in her life, repeating the violent ways of the past.