Their magic tree house takes Jack and Annie back to a monastery in medieval Ireland, where they try to retrieve a lost book while being menaced by Viking raiders.

Hiccup, the reluctant Viking hero, has three months, five days, and six hours to discover America, return to Berk, save his father, battle Polarserpents, and win the annual Inter-Tribal Friendly Swimming Race.

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?

Recounts the further escapades of Hiccup Horrendous Haddock the Third as he continues his Viking training during which he escapes from a boatload of Roman soldiers and searches for his kidnapped dragon.

"Hold on to your Viking helmets as you learn about the first known European to set foot on North America in this exciting addition to the Who Was? Series! Leif Erikson was born to be an explorer. His father, Erik the Red, had established the first European settlement in present-day Greenland, and although he didn't yet know it, Leif was destined to embark on an adventure of his own. The wise and striking Viking landed in the area known as Vinland...

"It is a time of political turmoil once more as the fading King Edward begins to lose control over his successors and their supporters. There are two potential heirs--possibly more--and doubt over whether the once separate states of Wessex and Mercia will hold together. Despite attempts at pulling him into the political fray, Uhtred of Bebbanburg cares solely about his beloved Northumbria and its continuing independence from southern control. But...