Batman is attacked immediately after leaving Arkham City on a rooftop by the Electrocutioner. Turns out it was one of his employees that has simply upgraded his equipment. He mentions that Batman killed his boss. (Arkham Origins) He is easily defeated (of course) and Batman leaves him tied up for Gordon. The Arkham Knight appears and tells him that Batman has gotten old and will soon be facing someone that knows him all too well. He also mentions that other rogues, just like the Electrocutioner, will think they are in cahoots but the same thing will happen to all of them. AK then kills the Electrocutioner with his shotgun.

Gordan puts Officer Cash from the first two games in charge of the Arkham City cleanup. That area of the city sounds like it is a mess.

The next day Batman gives Tweedledee/Tweedledum a beat down.

Bruce has a ten hour meeting to try and get the wealthy/powerful together to address the issue. Bruce Wayne mentions to Lucius that Gotham has no real mayor at the moment, just a deputy mayor that is worthless and can't make decisions.

The Joker's body is cut open during the autopsy. He has an artificial skin on with a flash drive hidden underneath. His Joker toxin comes out of the drive.

Cut to the Batcave. Joker comes on TV with a prerecorded message. He says he is coming to us "dead from somewhere in Gotham". He offers a 100 million reward for whoever can return his dead body to Harley Quinn.

Penguin has hired the Abramovici Twins, and gives them an assignment to find Scarecrow who has been missing since the events of Arkham Asylum. He also mentions that his target is Wayne Enterprises, and he is interested in restoring his family at the head of Gotham.

Batman tells Oracle that a second message was hidden in the Joker's broadcast for him alone. Joker has hidden bombs throughout the walls of Gotham, and they will be detonated unless Batman goes back to the Asylum.

Batman arrives at an empty Arkham Asylum. Welcome Home is written on the floor.