Big Brother Help Me!

Part three in my HTTYD stories. Started with Brother where are you? So read that and my one shot to understand what's going on. Valhalla has come under attack as a great evil has now taken over and everyone there is being tortured. Una comes back to Earth to get help from her big brother Hiccup. Can he and all of Berk save the all the souls in the afterlife? or will they fail?