Twelve-year-old Hilly has landed her dream job, riding on the set of Brunhilda, an epic film based on the fearless warrior of Icelandic legend. Norse fire ritual tells that on midsummer's day animals and humans can shapeshift, and one night Hilly finds herself connected to the young warrior and her fire stallion. As the two girls' lives intertwine, Hilly soon realises that they'll both have to risk everything for the love of their horses...