Mysterious Rider

Hiccup was five years old when he was snatched up by a Night Fury in a raid and was never seen again. 15 years later, Berk is on another hunt for the nest, but things go wrong when a storm hits and the Chief, his wife and Gobber are stranded in an icy wasteland. While searching for shelter they're ambushed by dragons and taken to a mysterious place where they find someone who they never thought they'd see again.