Set1,300yearsaftertheeventsofHowToTrainYourDragon,dragonsarenowjustalegendtothemodernworld.Whenageologicalanomalyopensupanimmense,miles-deepfissureintheEarth’ssurface,scientistsfromallovertheworldgatheratanewresearchfacilitytostudythemysteriousphenomenon.Soonagroupofmisfitkids,broughttothesitebytheirparents,uncoverthetruthaboutdragonsandwherethey’vebeenhiding--asecrettheymustkeeptothemselvestoprotectwhatthey’vediscovered.