A. J. Kane

Now chief and ruler of Berk alongside Astrid, Hiccup has created a gloriously chaotic dragon utopia. When the sudden appearance of a female of Toothless' kind coincides with the darkest threat their village has ever faced, man and dragon must leave the only home they've known, and journey to a hidden world thought only to exist in myth. As their true destines are revealed, dragons and riders will fight together to protect everything they've grown...