The main character of the cartoon – Hiccup (Jay Baruchel), born in the age of dragons – has changed the lives of the Vikings forever. Now Vikings and dragons live together in harmony with each other. One day Hiccup and his dragon Toothless meet the Day Fury, which opens a secret world of dragons for them. This discovery changes Hiccup's life and endangers all Vikings. The Vikings have to leave their settlement and fight back the ruthless dragon hunter.