The story focuses more on Humongously Hotshot and his back story than it does on Hiccup, which was weird, considering Hiccup has to find a way to stop an exploding volcano. There's a lot of explanation about Valhallarama (Hiccup's mom), which seemed like an odd choice, seeing as how she's usually off questing, and hasn't really been important to the series before now.
But, in retrospect (having read the next few books), I can see that this book marked a sort of turning point in the series. The stories start to focus a bit more on how Hiccup becomes the man writing the memoirs, rather than just recounting past adventures.
I love how everyone *still* seems to develop amnesia about Hiccup's past accomplishments. No matter how much this poor kid does, no matter how many times he saves everybody's lives, he's still the laughingstock of Berk (well, him and Fishlegs). Will the poor kid ever get a break?