A Viking teenager called Hiccup is a misfit in his tribe and an embarrassment to his father, the Chief. He tries his best to learn how to fit in and succeed when he is forced into dragon hunter school. His off-kilter view of life will change his world and the future of his tribe.
As he wanders the area around the school, he discovers an injured dragon and they become friends. He asks his school teacher if anyone has ever tried to train a dragon and is told no one has ever survived that.
With the life of his dragon on the line, he works to train it to carry him. He then introduces a friend from school to his dragon. Eventually, the entire dragon slaying class is onboard with his plans. His goal is to stop the senseless war between the Vikings and the dragons.