How To Break A Dragon's Heart  the eighth in the dragon series by Cressida Cowell and was published on September 3, 2009.  

The audio version, narrated by David Tennant, and was released on October 6, 2011.  

The US release date was December 19, 2011 from Hachette Children's Books.

The runtime is 4 hours and 37 minutes.

Synopsis: "Hiccup must battle Berserks, dodge Scarers, complete the Impossible Task and save Fishlegs from being fed to the Beast! And all while being hunted down by an old enemy with a dark secret about the Lost Throne. What's a Hero to do?"