Gwylliaid Cochion Mawddwy

This is the fourth tale in the series of 5 books, aimed at children aged 7-9 years who are able to read independently. The Gwylliaid are wild, they've blood-stained hands, and they're set on terrorizing the people and breaking the law in the Mawddwy area. Baron Owain is determined to catch them and punish them, but they are equally determined to have revenge on him.