The Flash 5x22 "Legacy" Season 5 Episode 22 Promo Trailer (Season Finale) - BARRY FACES OFF WITH REVERSE FLASH – Barry (Grant Gustin) faces off with his oldest, and most formidable nemesis, Reverse Flash (Tom Cavanagh). Gregory Smith directed the episode with story by Lauren Certo and teleplay by Todd Helbing & Eric Wallace (#522). Original airdate 5/14/2019.