Letting you know what's going on

Set when Hiccup and the group are aged 17-18, Hiccups starting to get stressed out. When he gets angry and goes to an island where Dagur the deranged has hid for the past 3 years, Hiccup discovers that the group and their dragons have been taken by Dagur. He also sees how willed Dagur is to take Toothless, and now even Berk for himself.