Darien Fawkes (Vincent Ventresca) is a petty thief, whose scientist brother chooses him for an experiment: the implantation of a special grant that generates "Quicksilver," a substance that can cover persons or objects and renders them invisible. When Darien's brother dies by those seeking the secret of the gland, Darien now holds the unique prototype. In return for government protection, Darien agrees to work for the government, partnering with secret agent Bobby Hobbes (Paul Ben-Victor), and under the supervision of The Official (Eddie Jones). Unfortunately, the Quicksilver glands has an unfortunate side effect: it drives the user insane unless they receive regular doses of a counter-agent. scientist Claire Keeply (Shannon Kenny) is charged with keeping Darien sane, and trying to find a way to remove the gland. In the second season, agent Alex Monroe (Brandy Ledford) joins the team.