If you are a fan of the Daredevil and Jessica Jones series, then you know that they are connected, just like Marvel and Netflix's series Luke Cage and Iron Fist. This was, of course, planned from the start to have these series be part of Marvel's Cinematic Universe, and all these characters will join on The Defenders, but where is the storyline going?
If you know anything about Daredevil Season 2, then chances are, you probably have at least heard that it is based on Marvel comics. There has been a lot of pressure to add characters that are famous to the franchise, like Elektra and Bullseye, characters even those who are not fans of the comics might recognize from the 2003 Ben Affleck movie version.
The good news is the Elektra will be making an appearance in Season 2, and she will be played by Elodie Yung. So far, there hasn't been any news that Bullseye will be making any appearances in Season 2, as we probably would have heard about that. There is a report in the International Business Times saying that action star Jason Statham was offered the role but supposedly passed because the character would not be prioritized on the show.
In fact, it looks like greater priority will be given to The Punisher as "the villain" for Season 2. Technically, the Punisher (Jon Bernthal) is a hero (actually an anti-hero) who kills criminals instead of arresting them. It is obvious that Matt Murdock (Daredevil's real name, played by actor Charlie Cox) is going to have his hands full with thwarting the gun-toting vigilante, and there may be a love interest going on with Elektra. In the comic, Matt developed relationships with Elektra and Karen Page (Deborah Ann Woll), and it will be interesting to see what direction the show goes from there.
As for Jessica Jones, there isn't too much known about this second season, and it might not air until 2017. From where it left off, Jessica had started her agency, and Movie Pilot suggests that it could be in full swing by the beginning of Season 2. It also suggests that the character Nuke (inspired by Daredevil comics source material) could surface, as the character of Will Simpson (Wil Traval) was set up to be this militant killing machine. This character could be another crossover character like the Night Nurse (Rosaria Dawson) who has appeared on both shows and is scheduled to appear in Luke Cage.
Luke Cage pretty well flushed out, according to its IMDB page. The character of Luke Cage (Mike Colter) was indeed flushed out as well in Jessica Jones, making it a very smooth transition for these Marvel Netflix shows. What is not flushed out hardly at all, it seems, is the show Iron Fist. About the only thing known from that is that Jeryn Hogarth (Carrie-Anne Moss), a character introduced in Jessica Jones, will be on it. There is no word of who will be playing Iron Fist as yet.
So far, the darker Netflix universe is set up for vigilantes who take their fights to the streets rather than huge brawls like the Avengers. If you have seen Ant-Man, then you may have noticed that people have not been trusting the Avengers as much as before since events in Avengers: Age of Ultron. Even Hank Pym (Michael Douglas) wanted to blame the Avengers for "dropping cities", and considering that the Avengers made Ultron, the average public might be in doubts about these heroes.
This could come into play especially after the events of Captain America: Civil War, where the heroes of Captain America and Iron Man will fight each other. Assuming that the Marvel Cinematic Universe and Netflix movies follow the same chronology, this means that the public could be introduced to the anti-hero The Punisher, and be all the more distrustful of superheroes. This would mean that by the time Captain America: Civil War ends, they might want to have anything to do with superheroes.
This is the type of the world that The Defenders could be a part of, and become a band of outlaw heroes. We'll get a good taste of it on March 18, 2016 when Daredevil returns for a second season. Sometime in 2016 (maybe as early as April), Luke Cage will appear, followed sometime in 2016 or 2017 by Iron Fist. The Defenders could appear before or after Season 2 of Jessica Jones.