Batman Beyond is a continuation of Batman the animated series. In the year of 2039, Batman of course continues to fight for justice for several decades after the end of the animated series. The only thing that forced him to retire was a heart condition, most likely brought on by overexertion of his body over the years.
Bruce Wayne and his vigilante crusade retires around the age of 60, several years after his self-imposed retirement. Bruce Wayne meets Terry McGinnis (who takes the title of Batman) after Terry is chased to his house by a gang calling themselves The Jokers, which they believe it carries on The Joker's twisted ideology of simply spreading chaos and anarchy. Bruce Wayne is forced to come out of his house and beat up several gang members until they run away. Terry McGinnis gives a disc to Bruce Wayne on his way out. Terry stumbles into the Batcave and decides on a whim to steal a Batsuit from Bruce Wayne's collection. He happens to steal one of the most advanced Batsuits that Bruce Wayne has at the time without testing out the suit's capabilities. Terry McGinnis goes after the man he believes to be responsible for ordering the murder of his father, Derek Powers. Terry finds Derek Powers on the docks getting rid of some toxic waste. Mr. Powers' bodyguard remember, by the name of Mr. Fix, fights with Terry and gets a brief upperhand when Terry's Batsuit freezes upon him. He later learns that Bruce Wayne seized control of the suit through some sort of interface with the bat computer in the Batcave. Terry explains what he is trying to do to Bruce Wayne, so then he allows Terry to have control of the suit to defeat the adversary. During the fight, Mr. fix is pushed into electrical wires and electrocuted. Derek Powers, on the other hand, does his best to run away. However, several barrels of the chemicals that Powers was trying to dump into the ocean get splashed onto him.
Terry McGinnis retreats and returns the Batsuit to Bruce Wayne and then leaves Bruce Wayne's house a couple days later. Bruce Wayne comes to Terry McGinnis' house to speak with him and his mother. Bruce Wayne offers Terry a job working for him as an assistant. Terry's mother is ecstatic. Terry, however, is more subdued, but accepts the offer. Bruce Wayne offers him the job as a cover for Terry taking over as Batman because of the altercation with Powers. Bruce Wayne saw bits and pieces of himself in Terry.
There are several villains that are introduced throughout the series. Some examples of which are Inc., a woman who can change her body from solid to an inky liquid substance. She is an assassin for hire, mainly working for anyone with the deepest pockets. Another villain that gets introduced in this series is called Shriek, a sound training engineer who developed a suit to weaponize sound waves. The ironic thing is his nervous system is so interconnected with the suit that when Batman accidentally damaged one of his sound emitters, it causes Shriek to go deaf, and the only way he can hear is throuhg the suit. There is also Spellbinder, a psychologist who feels he is not getting paid enough at his job. He uses a mixture of hypnotic suggestion and holographic technology to feed an image directly into the victim's brain, which makes them steal for him without them knowing.
I thought the show was fantastic when I watched it and I thought it was a worthy successor to Batman the animated series. I just wish they had ended it with Terry making his own version of the Batsuit. I've seen recently that there is been renewed interest in the series and hopefully that means they will start producing new episodes at some point in the future. Hopefully.