Batman's Final Mission

It has been 20 whole years since the Batman retired. After murdering the dark knights from the dark multiverse. And right after that Joker had Faked his own death. And most criminals didn't escape.Wich gave Bruce the idea to retire. His nemesis gone like most of his rogues. After the ten years Bruce was very old till the point he couldn't fight anymore without special equipment. In the ten years Gotham had turned in a shit city full of crime. More than ever even successors of his rogues stood up. To make chaos in Gotham. Then even Joker presented him to be a life and well. Ready for his biggest Joke ever wich was turning the entire United States in his Joker toxin. Now the whole world depended on the Bat to return. Now Bruce is back for one final mission.