Animated series “Batman Beyond” debuted on former network The WB Kids on this day in 1999. The prologue initially began in 2019 after Justice League and Justice League Unlimited. From Wipekedia: An aging Bruce Wayne, despite suffering from health complications continues to fight crime as Batman in a new high-tech Batsuit, though having increased difficulty in handling criminals. Bruce Wayne ultimately but reluctantly decides that he has grown too old for his crusade and retires from crime-fighting and shuts down the Batcave. By this time, his butler and father-figure Alfred Pennyworth and longtime allies (Commissioner James W. Gordon, Lucius Fox, Hamilton Hill, Leslie Thompkins, Renee Montoya, Harvey Bullock, Summer Gleeson and Amanda Waller) have either died or retired; his partners (Dick Grayson, Barbara Gordon, Tim Drake and Selina Kyle) are still alive and have severed their ties with him after a falling out before their retirements from their alter egos; all of his foes (The Joker, Harley Quinn, The Penguin, The Riddler, Two-Face, The Scarecrow, Mr. Freeze, Poison Ivy, Bane, Killer Croc, Clayface, Man-Bat, Deadshot, The Mad Hatter, Ra’s al Ghul and his daughter Talia, Phantasm, the Ventriloquist and Scarface, the Firefly, and Hugo Strange) are either retired, reformed, incarcerated (with or without parole), in exile, disappeared, or dead, and he had resigned from the Justice League.
The story then begins 20 years later to 2039 in Neo-Gotham, a futuristic version of the old Gotham City and a megalopolis featuring staggering high rises and flying vehicles. Bruce is now an elderly man in his 70s and a recluse living in bitter isolation in Wayne Manor, with no other companion but his guard dog Ace. Despite having retired primarily due to failing health and old age, it is strongly hinted (he retained the costumes of his former partners and continued to fight ignoring his aging) that he had suffered a traumatic event years before his health began failing which also contributed to his ultimate decision in addition to being still haunted by the fact that he used a cowardly weapon in his final mission to save himself.
Terry McGinnis is an athletic 16-year-old high school student and reformed troublemaker with a deeply ingrained sense of social justice. Living on difficult terms with his father Warren McGinnis, Terry disobeys his curfew one night to meet up with his girlfriend Dana Tan, only to incur the wrath of a group of the gang called the Jokerz harassing them. A high-speed motorcycle chase between Terry and the Jokerz leads them to the grounds of Wayne Manor, where they run into the elderly Bruce Wayne. Bruce and Terry fend off the Jokerz side-by-side, but the exertion aggravates Bruce’s heart condition. Terry helps Bruce back to the manor and, while exploring the mansion after realizing that he is unable to leave the mansion as Ace is guarding it, stumbles upon the entrance to the Batcave and thus discovers Bruce’s secrets, only to be chased out by an angered Bruce.
“Batman Beyond” aired for three seasons, producing 52 episodes in total.