Talli is a Summoner: a nearly extinct people, hunted by those who fear their mysterious powers. As a baby, she was adopted by Lord Borin, and all was well for many years... But one day, their castle is sacked by Borin's rival, Lord Ulric. Talli escapes in the chaos and darkness with the help of the noble (some might say too noble) knight Sir Alan.

With Ulric's forces hot on her heels, Talli and Alan keep one step ahead, gathering a motley crew of companions and protectors that includes the lethargic-but-incredible swordsman Lélo. Ulric's ruthless Captain Nina pursues them doggedly, but she is unaware of the secret of Talli's blood: the secret of the Summoners!