Fighting Fire With Fire

"Fighting Fire With Fire" is the fifteenth episode of the fifth season of Arrow, and the one-hundred-and-seventh episode overall.

Synopsis
Oliver faces his biggest challenge yet as mayor. Felicity continues down her dark path with Helix. After Vigilante attacks Oliver while he's acting as the mayor, Diggle leads the team in a mission to stop Vigilante once and for all.

Production
Preparation ran from December 12, 2016 until January 5, 2017. Shooting ran from January 6 until January 17, 2017.