To complete the next step in her witch's training, Cassie Morgan must invent a brand-new spell. However, she is struggling for inspiration - so she jumps at the chance to attend the Covenmoot.

Every five years, covens from all over Britain and Ireland meet to take part in a series of challenging games in the hopes of winning the Covenmoot Cauldron. Cassie and her friends travel to Glen Carlin, a remote valley in the Scottish Highlands, to take part. But menacing forces haunt the moors and rumours of the ancient Stonewitch swirl through the camp.

Cassie and her coven must work together to prove themselves in the Covenmoot, while long-hidden secrets come to light and the wicked Erl King's power grows.