The Batman: Season 4

After a young circus performer named Richard Grayson loses his parents to a criminal named Tony Zucco, Bruce adopts the boy, since he knows what it feels like to lose his family. Batman then sets out to bring Mr. and Mrs. Grayson's killer to justice. Once Bruce's secret is revealed, Richard joins Batman as his new sidekick, Robin.

After watching a film about criminal masterminds, Penguin forms Team Penguin along with Killer Croc, Ragdoll, Firefly and newcomer Killer Moth to finally take Batman down. Meanwhile, Batgirl and Robin must learn how to work together. Moth gets infected by a chemical which the team stole and mutates into a giant, monstrous moth.

After Ethan Bennett foils one of Joker's plans, he plans to prove himself to Batman by turning a new leaf. Meanwhile, has-been actor Basil Karlo steals the mutagen responsible for mutating Bennett and becomes the new Clayface. Batman is unsure if he can trust Ethan enough to let him help stop Karlo.

When evidence from a series of art thefts by the Everywhere Man, a new costumed villain with the power to replicate, implicates Bruce's close friend John Marlowe, Batman believes there must be another explanation. Now, Batman must unmask the identity of the "Everywhere Man" and prove his friend's innocence.

After Batman apprehends Black Mask, his henchmen plan to spring him from Gotham P.D. so that Black Mask can activate his doomsday device. When Batman is captured, Batgirl and Robin must stop the villain and save the city on their own.

Hugo Strange infects the population of Gotham City with a virus that transforms them into zombies, and only Batman and Robin are left to find and distribute the antidote. But when Robin falls, only Batman can save the day. But not everything is at it seems ...

A thousand years into the possible future, the citizens of new Gotham must uncover the history of Batman to stop a new-and-improved Mr. Freeze.

The Bat Team goes up against an unstoppable thief who knows their every move.

Riddler and Batman are in a crate, dropped at the bottom of Gotham Harbor. Riddler reveals his origins.

When pop psychology TV host Harleen Quinzel is canceled from her television program for ambushing Bruce Wayne and for her bad advice, Joker takes an interest and decides to turn her into his partner in crime, Harley Quinn.

The villains of Gotham are disappearing, each one defeated and captured by an invisible vigilante named Rumor. Batman and Robin must defeat Rumor before he has a chance to execute all the villains.

Bruce discovers that Wayne Industries is distributing alien technology across the world, and gains the aid of a mysterious new ally.

Martian Manhunter's prediction of an alien invasion by The Joining has come true. As Batman tries to stop them on his own, he learns that even working with a team will stop The Joining.