Batman Beyond (season 2, episode 24)

“Payback“ Release date: 05-13-00 Plot: A new vigilante who calls himself Payback begins taking revenge on the tormentors of several troubled teenagers, all of whom are in the same therapy group. When Terry goes undercover in the group to find the culprit, he begins to suspect the doctor running the sessions, but Payback’s real identity proves to be someone no one would have expected.