Set1,300yearsaftertheeventsofHowToTrainYourDragon,dragonsarenowjustalegendtothemodernworld.Whenageologicalanomalyopensupanimmense,miles-deepfissureintheEarth’ssurface,scientistsfromallovertheworldgatheratanewresearchfacilitytostudythemysteriousphenomenon.