This is the 3rd season in this anime series and should be the longest season according to its creators.
The story of Attack on Titan is about a cruel world in which there are a lot of titans which are basically huge creatures which are very similar to humans. But the bad part is that they like to eat humans! They have no mercy at all, therefore, the humans have to be stronger than them in order to beat them all of them and delete them from the world. The humans are guarded by huge walls which surround them and protect them from the Titans which are outside of the walls in the "outside" walls.
The main hero in the anime show is a teenager whose name is Eren has seen his mom gets eaten by a titan right before his eyes so he swears to kill all the titans in the world. He actually has the ability to turn into a titan himself but he will learn to use it later in the anime show.
This is the trailer of the new season:
You can watch the new season English subbed via this link: http://shingekikyojin3.net/
