Dr. Light is the evil Earth-2 counterpart of Linda Park, Barry Allen's former girlfriend, and she is a thief in from Earth-2 who was sent to Earth-1 by Zoom to kill The Flash. In the episode, "The Darkness and the Light," Dr. Light was committing one of her robberies when she encounters Barry, who is taken aback when he sees that Light revealed as Linda. At that exact instant, Light blinds Barry and escapes. Realizing that she has a doppleganger on Earth-1, Light attempts to kill Linda and assume her identity to escape from Zoom, but she accidentally kills Linda's boss. Light later attempts to leave Central City, but is again encountered by Barry, who speeds up to high levels to subdue her.
Light ended up captive at S.T.A.R. Labs, where the group planned to use her to lure Zoom into a trap. However, in the following episode, "Enter Zoom," the evil Dr. Light used her invisibility power to escape. Her whereabouts are currently unknown.