The Second Great War was the war in which the Humans of the Valley led by the Royal House of Harvestar against the Rat Creatures, led by Kingdok, for control over the valley. Although the Dragons had decided to withdraw from the Earth to dream, they decided to aid the Royal Family, this last time.
During a series of unpredictable attacks by the Rat Creatures, Atheia was severely damaged and the Royal Family managed to escape. Briar, The Hooded One betrayed her family, the Royal Family to the Rat Creatures. Thorn and Grandma Ben were able to escape to Deren Gard, but Thorn's Father and Lunaria Harvestar, the Queen, were both eaten alive by Kingdok, Briar also died.
This war marked the end of the Harvestar rule over the Valley, until Thorn restored the throne.