The clip, released on Tuesday, follows 10-year-old Jojo (Roman Griffin Davis) who joins the Hitler Youth organization in Germany where he learns to use weapons and burn books.
Jojo also has an imaginary friend -- a goofy-version of Hitler portrayed by Waititi.
Jojo's life and everything he believes in is turned upside down when he discovers that his mother (Johansson) is hiding a young Jewish girl (Thomasin McKenzie) inside their attic. Jojo becomes friends with the girl and starts to question his nationalism.
"They'll never win. Love is the strongest thing in the world," Johansson says.
The film is written by Waititi and based on the book Caging Skies by Christine Leunens.