Hiccup discovers a seemingly endless new island. During his exploration of it, he finds three gigantic walls and within them, remnants of a civilisation far more refined than his own. The only problems are the pests.

With only two working Jaegers left and the frequency of Kaiju attacks rising, humanity received a grim reminder. They were the prey and the Kaiju were the hunters. But when a mining team finds a tomb containing a preserved body of eons past, humanity will have to turn to their last hope-the original Jaeger 'pilot'.