Arrow 6×21 “Docket No. 11-19-41-73” Season 6 Episode 21 Sneak Peek – COLIN DONNELL GUEST STARS — The pressure mounts for Oliver (Stephen Amell) who begins to wonder if he will lose everything in his battle to save Star City. A familiar face returns. Andi Armaganian directed the episode with teleplay by Ubah Mohamed & Tyron B. Carter and story by Marc Guggenheim (#621). Original airdate 5/3/2018.