Andy Mientus is returning to The Flash to reprise his role as the Pied Piper in an episode set to involve time travel.
Pied Piper aka Hartley Rathaway was last seen escaping from Star Labs when he managed to trick Cisco in releasing him. When he returns in Episode 217 “Flash Back” he again comes into conflict with Team Flash and S.T.A.R. Labs. During the course of the episode somehow Flash finds himself revisiting a seemingly lost timeline.