How to Cheat a Dragon's Curse (How to Train Your Dragon #4) by Cressida Cowell
Reluctant hero Hiccup Horrendous Haddock III must rescue his best friend, Fishlegs, from the deadly disease Vorpentitis. The only cure is rare and almost 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.
Dog Gone Note: This book is in very good condition with barely noticeable signs of wear.