Ben Affleck is currently shooting his Prohibition-era crime film, Live By Night, so he's going to be busy for a little while. Not only that, but he's got press on the upcoming Batman v Superman: Dawn of Justice, and then he'll bring the Dark Knight over to Zack Snyder's Justice League films. With all of that going on it will be a long time before that solo Batman movie he's co-writing and maybe directing ever comes to be, but that hasn't stopped rumors from emerging about what it could entail. There COULD be spoilers to follow, assuming any of this true.
Joblo thinks they've uncovered details about the solo Batman movie's plot, which Affleck is co-writing with David Goyer. They say the film will include the Red Hood, who is actually the resurrected Jason Todd. Todd was Robin for a time but was murdered by the Joker in the classic "A Death in the Family" storyline. He was then brought back to life using one of those Lazarus Pits favored by Ra's Al Ghul and seen frequently in episodes of Arrow.
In 'Batman v Superman' there's said to be a shrine in honor of the fallen Todd in the Batcave. And that's not all as Dick Grayson, aka the first Robin, is also said to be making an appearance. He'll have grown up and taken on his Nightwing identity and will help Batman in his battle against Red Hood and the Joker (Jared Leto) who also figures into this. Nightwing will get a mention in 'Batman v Superman' but won't actually appear until the solo movie.
So take all of this with a grain of salt. Much of it sounds plausible, but consider that superhero movie screenplays tend to evolve over time. Certain characters and subplots are added while others fall away, and it's way too early to believe a story has been nailed down.
