When Penny Parker and her friend Louise go to the nearby swamp, they soon find themselves embroiled in intrigue. Louise loses her dog while there, and in the process of finding the dog, they find an abundance of mysteries to be solved Following along with their adventures in Swamp Island This book is from the Penny Parker series by Mildred A. Wirt, also known as ghostwriter Carolyn Keene, of the Nancy Drew series of books.