How to Train Your Dragon

The Viking village of Berk is frequently attacked by dragons that steal livestock and endanger the villagers. Hiccup, the 15-year-old son of the village chieftain, Stoick the Vast, is deemed too weak to fight, so he creates mechanical devices under apprenticeship with Gobber, the village blacksmith who is also Stoick's best friend and advisor. Hiccup uses a bolas launcher to shoot down a Night Fury, a rare dragon, during a dragon raid, but nobody believes him. He enters the forest and finds the Night Fury but cannot bring himself to kill the dragon. Instead, he sets the creature free. The Night Fury then suddenly pins Hiccup down, but to Hiccup's surprise, the dragon spares him.
Before leaving with his fleet to find and destroy the dragons' nest, Stoick enrolls Hiccup in a dragon-fighting class with fellow teenagers Fishlegs, Snotlout, twins Ruffnut and Tuffnut, and Astrid, on whom Hiccup has a crush. Facing little success in the class, Hiccup returns to the forest and finds the Night Fury in a cove, unable to fly because Hiccup's bolas tore off half of his tail fin. Hiccup gradually befriends the dragon, naming him "Toothless" after his retractable teeth, and designs a harness and prosthetic fin that allows Toothless to fly with Hiccup riding atop his back.
Learning dragon behavior from Toothless, Hiccup manages to pass the training by subduing the dragons, earning admiration from his peers but sparking suspicion and jealousy from Astrid. Stoick's fleet returns home unsuccessful. When Hiccup learns that he must kill a dragon for his final exam, he tries to run away with Toothless, but Astrid discovers them, and Hiccup takes her on a flight to demonstrate that Toothless is friendly. During the flight, Toothless is hypnotically drawn to the dragons' nest, where an evil gigantic dragon named the Red Death summons relatively smaller dragons to feed it copious amounts of live food to avoid being eaten themselves. Realizing the dragons have been forced to attack Berk to survive, Astrid wishes to tell the village, but Hiccup advises against it to protect Toothless.
In his final exam, Hiccup faces a captive Monstrous Nightmare and tries to subdue it to prove that dragons can be peaceful. When Stoick unintentionally enrages the dragon into attacking, Toothless arrives to protect Hiccup but is captured. Outraged, Stoick confronts Hiccup until he inadvertently tells him the location of the Dragon's Nest. Thinking Hiccup betrayed the village, Stoick rashly disowns his son for befriending a dragon and prepares the fleet using Toothless as a guide to search and destroy the nest after Hiccup tells him that Toothless brought him to the island. Astrid prompts Hiccup to realize he spared Toothless out of compassion, not weakness. Regaining his confidence, Hiccup shows his new friends how to befriend the training dragons, and they set out after their tribesmen.
Stoick and his Vikings locate and break open the dragons' nest, awakening the giant Red Death, which easily overwhelms them. Hiccup and his friends ride in on the training dragons, distracting the monster. Hiccup attempts to free Toothless, and Stoick, realizing his horrible mistake and his son was telling the truth, rescues and apologizes to both Hiccup and Toothless, telling Hiccup he is proud of him as his son. In a fierce midair battle, Hiccup and Toothless sets the Red Death's mouth ablaze, destroy its wing membranes, causing it to crash fatally and explode. Whilst escaping the resulting explosion, Hiccup gets knocked off Toothless. He is saved by Toothless, but loses his left foot in the process.
Some time later, Hiccup awakens back in Berk and finds dragons frolicking in the village and Gobber having fashioned new prosthetics for him and Toothless. Hiccup is now admired by his village, including Astrid, who at first punches him in the arm for scaring her before kissing him. Berk begins a new era of humans and dragons living in peace.