S4, E18: Brie Larvan aka the Bug-Eyed Bandit (returning guest star Emily Kinney) breaks out of jail and turns up at Palmer Tech threatening to kill everyone unless she gets the biochip that is implanted in Felicity's spine. When Oliver realizes that Felicity, Thea and Donna are trapped in Palmer Tech with everyone else, he looks to a surprising ally to help Team Arrow save the day.