This book is directly connected to Castle Rodriganda. It initially takes place in Germany, then returns to Mexico, with the main setting being the wild Mapimi, a desert in the northeast of the country. An ancient mysterious pyramid is at the center of the highly dramatic plot. The story is set in the late 1840s. It is an adaptation of the popular novel "Das Waldröschen." The Pyramid of the Sun God is part 2 of a six-part novel series. Part 1: Castle Rodriganda, Part 3: Benito Juarez, Part 4: Trapper Geierschnabel, Part 5: The Dying Emperor, Part 6: The Duke's Children. The title is also available as an e-book.