From the introduction: The Great Mire: a vast saltmarsh of reeds and mud, the haunt of the curlew, and the bane of travellers. Fishermen and farmers eke out a living on its margins, fearful of its wrath. This book is organised into three parts. This section describes the region of the Great Mire, its locations and its inhabitants – both human and otherwise. The second section is an adventure called A Secret in the Water, which introduces player characters to the region. The third part, Further Adventures, consists of a number of adventure outlines for further exploration of the Great Mire. These stories can be played individually or else woven together to form a mini-campaign. To use this book you will need a copy of the Mythras rules and also Mythic Britain. The Mythic Britain supplement Logres will also be useful, but is not required.