Young Eliza and her eleven brothers' lives are transformed when a plague ravages the Kingdom of the North and kills their mother, the Queen. When their father remarries, their brilliant and "unusual" new stepmother becomes obsessed with finding a cure for the plague and protecting her new family − so obsessed that she decides to turn the boys into swans so they can fly away from the plague, and to send Eliza to a far-away village the plague hasn't touched. Years later, the Queen discovers a cure for the plague just before she dies from it herself. With the kingdom in chaos, it's up to teenaged Eliza to find her brothers, break the Queen's spell on them, return home to cure the plague − and claim her rightful place in the kingdom!