The Premise
There's a lot going on here, as a lot of world-building needs to be done. As such, there will be a lot of characters here introduced that some may feel aren't given their due, but the goal I shot for was creating a comic-book-come-to-life feel for the film, so there will be a lot of cameos to establish a "lived in" look. For example, Barbara Gordon is already paralyzed and mentioned in conversation with the Commissoner, but not seen. I also made a few deviations from the source for the sake of the story. For example, as much as I love Tim Drake, there simply isn't room in the franchise at this point for him and Damian. As such, I opted to include Damian over Tim, as I feel he adds more to the overall story and Bruce's personal arc. The second major change was having Nightwing take Spoiler as his protege, both as a way to expand the Bat-Family faster and also to mirror the Batman/Robin partnership, which is a crucial plot point for the film. Lastly, Barbara Gordon has already been shot. She is only mentioned, but it will be later revealed that she became Batgirl, emulating Batman without his training, but was then paralyzed in action, contributing, along with Jason's death to Bruce's downwards spiral. Gordon remains unaware of the true circumstances of her injury. All in all, the film would come in at about the same time as TDKR and is divided into 3 distinct segments, detailed below.
Part 1: Jason Todd Lives
Given Cast: Ben Affleck: Bruce Wayne/Batman, Jeremy Irons: Alfred Pennyworth, J.K. Simmons: Jim Gordon
After the events of Justice League, Bruce Wayne is back in Gotham, trying to rebuild the shambles of both his day and night life, having burnt countless bridges in his downward spiral following the death of the second Robin, Jason Todd. Those he aims to reconcilewith include both Commissoner Gordon, who reluctantly agrees to resume his unofficial partnership with Batman, and Dick Grayson, now operating sas his own man, who wants nothing to do with his old mentor due to Bruce's recent personal failings. Things are complicated when a new vigilante calling himself the Red Hood begins to lethally dispatch figures in the Gotham underworld in an apparent attempt to draw out the Joker.
Having tracked the Red Hood, Batman realizes too late that he has targeted Arkham. He arrives in time to stop the murder of the inmates, but instead prompts a prison break. While the crazies flee into Gotham, Batman is distracted, dueling the Red Hood and ultimately unmasking him, revealing the believed dead Jason Todd. Taking advantage of the ensuing shock, Red Hood flees, leaving only a cryptic message for Batman.
Part 2: The Mystery
Given Cast: Joe Magnaniello: Deathstroke
Irrfan Kahn: Ra's al Ghul Sarah Shahi: Talia al Ghul
Robert Patrick: Jacob Kane Michael Emerson: Wintergreen
Against Alfred's advice, Bruce leaves Gotham detirmined to detirmine to uncover the truth behind Jason's apparent return. Having recognized the Red Hood's fighting style as one taught by the League of Assasins, his first move is to track down those who may know the location of Ra's al Ghul. His first stop takes him to his uncle, Jacob Kane. As one of the few aware of Bruce's secret, he helps in the source despite Bruce denying a need for asistance. The trail then leads him on a hunt for the mercenary Deathstroke. After an intense search, the two meet, and Bruce aquires the final lead to track down Ra's, as well as a confirmation of respect from Slade Wilson.
Batman infiltrates the LoA's new base with seemingly little resistance, only to have a trap sprung on him once inside. Ra's confronts him willingly with the answers he wants: After Bruce refused his place as Ra's' heir, he settled on the next best thing: the "Son of the Bat", stealing Jason's body and reviving him in the Lazarus Pit. Jason trained under Ra's, but ultimately abandoned the League like his father. At this point, Ra's turned instead to a literal son of Batman. Talia seduced Bruce, and the resulting child was genetically modified and grown to fighting age at an accelerated rate to produce the perfect assasin. Confronted with this shocking turn of events, Batman breaks free, takes Damian, and fights his way out of the League's base.
Part 3: The Red Hood and The Joker
Given Cast: Jared Leto: The Joker, Margot Robbie: Harley Quinn
Clarke Peters: Lucius Fox
In Joker's absence, the recently released Arkham inmates have wrecked havoc on Gotham, causing an exasperated Nightwing to set up shop in the Batcave with Spoiler to take on the new threats. The chaos, meanwhile, has succeeded in drawing The Joker back to Gotham, Harley Quinn in tow, to reclaim his place as the Clown Prince of Crime. However, the remaining mob bosses have had enough of the Red Hood, and hire Deathstroke to take him down. Batman returns, Damian in tow, just as the Joker makes his move, kidnapping numerous Gotham denizens from both sides of the law and demanding tribute from all interested parties. Bruce and Dick move past their differences to stop the violence, leaving Joker and Harley holed up in their new base, rigged to explode on command. It soon becomes apparent that the Red Hood is inside, murdering the criminal hostages. Both Batman and Deathstroke break in, starting a game of cat and mouse between them, the Joker, and Red Hood. With the building primed to blow, Batman deals with Slade, who removes the remaining hostages. Meanwhile, Jason reveals himself to Joker, who tries to sacrifice Harley to save his life. Jason will have none of it, and Batman arrives to save Harley and confront Jason. The standoff plays out similar to the events of the original comics, with Joker ultimately blowing the building and Batman barely escaping with Harley.
In the aftermath, Bruce's new world is finalized as he mends his last broken relationship, with Dick. Now with a new outlook on life, he moves to establish a new status quo, detirmined to train his son and refusing to give up on Jason, as no bodies were recovered from the destroyed base. Harley is returned to Belle Reeve, Nightwing and Spoiler return to Bludhaven, Alfred begins to craft a new Robin suit, and Deathstroke goes back to business as usual. Teases are placed both for Barbara Gordon's return to Gotham and the arrival of Batwoman.
POST CREDITS
-Ra's makes a deal with Amanda Waller, setting up a role in the Suicide Squad sequel.
-Jason, having survived the destruction, picks up on the trail of a new threat and drives off into the sunset.