Concerned that Alvin and the Outcast Tribe are planning an attack on Berk, Stoick institutes flight restrictions on the dragon academy. Certain that Alvin will also use his newfound dragon-training knowledge to bolster any attack, Hiccup forms a secret "Dragon Flight Club" in order to train the kids to defend Berk against a potential dragon army-not realizing that Stoick's flight ban was for everyone except Stoick himself. Alvin and the Outcasts then attack Berk, and while the riders are defending against the attack, Savage plant Whispering Death eggs in the caverns under Berk...