How to Cheat a Dragon's Curse (How to Train Your Dragon Series #4)

Reluctant hero Hiccup Horrendous Haddock III must rescue his best friend, Fishlegs, from the deadly disease Vorpentitis. The only cure is rare and impossible to find... a potato. But where will Hiccup find such a thing? He'll have to dodge the terrible Sharkworms Battle Doomfangs, and outwit crazy Hooligans if he's going to be a Hero. Again.