The Loki Wolf — Arthur Slade

When Angie dreams about being devoured by a giant wolf, her parents tell her it is only her imagination. But later, while on vacation in Iceland with her grandfather and two cousins, she begins to wonder if the dream wasn't a warning. First, there are strange scratches outside her window. Then she finds out that sheep have recently been disappearing from her uncle's farm. But it isn't until she and her cousins go to the old croft house that they discover the horrifying truth.