Special Guest Stars Victor Garber as Dr. Martin Stein / Firestorm Guest Stars John Wesley Shipp as Dr. Henry Allen Robbie Amell as Ronald "Ronnie" Raymond / Firestorm Andy Mientus as Hartley Rathaway Melise as Linda Park Britne Oldford as Shawna Baez Micah Joe Parker as Clay Co Starring Scott McNeil as Julius Doug Chapman as City Worker #1 J. Douglas Stewart as Fire Chief Tristan Shire as Bartender Crystal Mudry as Woman Fraser Aitcheson as City Worker #2 Jerry Trimble as Marcus Stockheimer Matt Yanagiya as Man Theo Wiersma as Karaoke Bar Patron Will E. McDonald as Truck Guard #1