The story of A Song of Ice and Fire takes place in a fictional world, primarily upon a continent called Westeros but also on a large landmass to the east, known as Essos.[5] Most of the characters are human but as the series progresses other races are introduced, such as the cold and menacing Others from the far North and fire-breathing dragons from the East, both races thought to be extinct by the people of the story. There are three principal storylines in the series: the chronicling of a dynastic civil war for control of Westeros between several competing families; the rising threat of the Others who dwell beyond an immense wall of ice that forms Westeros' northern border; and the ambition of Daenerys Targaryen, the exiled daughter of a king who was murdered in another civil war fifteen years previously, to return to Westeros and claim her rightful throne. As the series progresses, all three storylines become increasingly interwoven and dependent on each other.