Return of the Dragon Princess
If you haven't read the story Daughter of the Dragon, go read it now before you start reading this!
Two years after the war against the dragon hunters and after the battle against Drago Bludvist, Ash is finally free to go home. But after an attempted assassination on Ash, Hiccup is reluctant to let the dragon princess leave Berk for fear she will be harmed. He has her stay on Berk but has a bodyguard of his choice to protect her. Unfortunately for Ash, it's someone she has been butting heads since the moment they met.