It's the height of summer and the palace is full of ambassadors and ladies from the Spanish court. When a visit to the famous St Bartholomew's fair is planned to entertain the guests, Grace jumps at the chance to get out for the day. Not everybody feels the same though and there's a lot of superstision amongst the ladies about the gypsies, fortune tellers and herbal medicine that will be at the fair.

When a mysterious fire at the fair leaves Lady Sarah injured and a gypsy woman dead, it seems the ladies were right to be worried. But was the fire started on purpose? And can Grace get to the bottom of this mystery?