Nazis are bad. Nazis messing with experimental technology and supernatural powers can only be worse. If you ever wondered what it would be like if Nazi Germany had not lost World War 2, the Wolfenstein series is the franchise for you.
However, the series has two plots you should take into account if are considering giving the franchise a shot. Up to and including Wolfenstein (2009), the stories take place during World War 2, and you play as famous agent of the Office of Secret Actions B.J. Blaskowicz, who is sent deep behind enemy lines to investigate experiments and paranormal activity conducted by the Paranormal Division of the SS.
Since the series reboot in 2014, the plot revolves around a world in which Nazi Germany was victorious in successfully defeating the United States and its allies and is now acting as an occupying force in the continental United States. Still playing as Blaskowicz, you lead a resistance fight against the Nazi occupiers, who have augmented their forces with bizarre technology.