Legend of Heart of Dragon

It had been a year since the battle with Drago Bludvist. Berk had changed a lot, with Hiccup as chief and Toothless as alpha. Things couldn't be better for Hiccup and his friends. What happens when Hiccup and Fishlegs come across an old legend about the Heart of Dragon. What happens when an unknown dragon rider with a night fury, a female for that manner, shows up at Berk?

Why is Hiccup experiencing weird abilities such as talking to dragons and only the unknown rider can help him? What happens when trouble lurks at the corner since the mystery rider arrived?
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* I'm back!! I'm still having trouble writing, but I'm not letting you guys down. Updates will be slow though*