In this episode Trader Johann has something important for Stoick to receive, yet Stoick has not received it and goes out looking for Johann. When not found, Hiccup and company (much to Hiccup's annoyance) head out to find Johann and receive this item. They find him adrift on part of what was his boat, and apparently the item was not for Stoick but for Hiccup; not only that, but the item is now lost to what Johann and the majority of the riders believe to be the 'Fog Monster'.
It was easy to guess what the 'Fog Monster' was going to be. The new dragon in this episode is interesting, though I didn't love it as much as I've loved the other ones introduced in the series, such as the Whispering Death. It was nice to have a slight focus on Hiccup's mother for the first time, too. It didn't have anything important plot wise, but it was lovely all the same.
This was a good, unique story with some nice scenes. Not good enough for a nine, but easily worthy of an eight.